Plugin cannot start due to invalid plugin.xml

[thecodingrobot]

GoCD 16.10.0 fails to load the plugin with the following error message:

2016-10-05 14:08:54,784 [Thread-5 ] WARN  plugin.infra.plugininfo.GoPluginDescriptorBuilder:72 - Could not load plugin with jar filename:github-pr-comment-scalastyle-1.2.jar
org.xml.sax.SAXException: XML Schema validation of Plugin Descriptor(plugin.xml) failed
org.xml.sax.SAXParseException; lineNumber: 2; columnNumber: 60; cvc-datatype-valid.1.2.1: '1.2' is not a valid value for 'integer'.
        at com.thoughtworks.go.plugin.infra.plugininfo.GoPluginDescriptorParser$1.error(GoPluginDescriptorParser.java:107)
        at org.apache.commons.digester.Digester.error(Digester.java:1639)
        at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:137)
        at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:396)
        at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327)
        at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:284)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:452)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3230)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.processOneAttribute(XMLSchemaValidator.java:2825)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.processAttributes(XMLSchemaValidator.java:2762)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:2050)
        at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:740)
        at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:745)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1364)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$ContentDriver.scanRootElementHook(XMLDocumentScannerImpl.java:1295)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3135)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:880)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
        at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)
        at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)
        at org.apache.commons.digester.Digester.parse(Digester.java:1765)
        at com.thoughtworks.go.plugin.infra.plugininfo.GoPluginDescriptorParser.parseXML(GoPluginDescriptorParser.java:91)
        at com.thoughtworks.go.plugin.infra.plugininfo.GoPluginDescriptorBuilder.build(GoPluginDescriptorBuilder.java:70)
        at com.thoughtworks.go.plugin.infra.listeners.DefaultPluginJarChangeListener.pluginJarAdded(DefaultPluginJarChangeListener.java:68)
        at com.thoughtworks.go.plugin.infra.monitor.DefaultPluginJarLocationMonitor$PluginLocationMonitorThread$DoOnAllListeners$1.execute(DefaultPluginJarLocationMonitor.java:288)
        at com.thoughtworks.go.plugin.infra.monitor.DefaultPluginJarLocationMonitor$PluginLocationMonitorThread$DoOnAllListeners.doOnAllPluginJarChangeListener(DefaultPluginJarLocationMonitor.java:319)
        at com.thoughtworks.go.plugin.infra.monitor.DefaultPluginJarLocationMonitor$PluginLocationMonitorThread$DoOnAllListeners.pluginJarAdded(DefaultPluginJarLocationMonitor.java:286)
        at com.thoughtworks.go.plugin.infra.monitor.DefaultPluginJarLocationMonitor$PluginLocationMonitorThread.notifyListenersOfAddedPlugins(DefaultPluginJarLocationMonitor.java:210)
        at com.thoughtworks.go.plugin.infra.monitor.DefaultPluginJarLocationMonitor$PluginLocationMonitorThread.loadAndNotifyPluginsFrom(DefaultPluginJarLocationMonitor.java:198)
        at com.thoughtworks.go.plugin.infra.monitor.DefaultPluginJarLocationMonitor$PluginLocationMonitorThread.run(DefaultPluginJarLocationMonitor.java:184)
Caused by: org.xml.sax.SAXParseException; lineNumber: 2; columnNumber: 60; cvc-datatype-valid.1.2.1: '1.2' is not a valid value for 'integer'.
        at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203)
        at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
        ... 31 more

This is because it plugin.xml does not pass the XSD validation (https://github.com/gocd/gocd/blob/master/plugin-infra/go-plugin-api/resources/plugin-descriptor.xsd)
The version attribute of the <go-plugin/> tag should be an integer.
https://github.com/insano10/gocd-pr-comment-scalastyle/blob/master/src/main/resources/plugin.xml#L2

The plugin version itself goes into about/plugin which is a string.