prepare for 3.8.6 release

README.md

@@ -540,7 +540,7 @@ Add the XChart library as a dependency to your pom.xml file:
     <dependency>
         <groupId>org.knowm.xchart</groupId>
         <artifactId>xchart</artifactId>
-        <version>3.8.5</version>
+        <version>3.8.6</version>
     </dependency>
 ```
 
@@ -556,7 +556,7 @@ For snapshots, add the following to your pom.xml file:
     <dependency>
       <groupId>org.knowm.xchart</groupId>
       <artifactId>xchart</artifactId>
-      <version>3.8.6-SNAPSHOT</version>
+      <version>3.8.7-SNAPSHOT</version>
     </dependency>
 ```
 
@@ -567,7 +567,7 @@ Snapshots can be manually downloaded from Sonatype: [https://oss.sonatype.org/co
 To use XChart with the Scala Build Tool (SBT) add the following to your build.sbt
 
 ```scala
-libraryDependencies += "org.knowm.xchart" % "xchart" % "3.8.5" exclude("de.erichseifert.vectorgraphics2d", "VectorGraphics2D") withSources()
+libraryDependencies += "org.knowm.xchart" % "xchart" % "3.8.6" exclude("de.erichseifert.vectorgraphics2d", "VectorGraphics2D") withSources()
 ```
 
 ## Building with Maven
@@ -597,15 +597,15 @@ In the plugins section in IntelliJ search for `google-java-format` and install t
 
 ![](https://raw.githubusercontent.com/knowm/XChart/develop/etc/XChart_Demo.png)
 
-- Linux: execute command `java -cp xchart-demo-3.8.5.jar:xchart-3.8.5.jar org.knowm.xchart.demo.XChartDemo`.
+- Linux: execute command `java -cp xchart-demo-3.8.6.jar:xchart-3.8.6.jar org.knowm.xchart.demo.XChartDemo`.
 
-- Windows: In the cmd command window, execute the command `java -cp xchart-demo-3.8.5.jar;xchart-3.8.5.jar org.knowm.xchart.demo.XChartDemo`; In 
-  the PowerShell command window, execute the command `java -cp "xchart-demo-3.8.5.jar;xchart-3.8.5.jar" org.knowm.xchart.demo.XChartDemo`.
+- Windows: In the cmd command window, execute the command `java -cp xchart-demo-3.8.6.jar;xchart-3.8.6.jar org.knowm.xchart.demo.XChartDemo`; In 
+  the PowerShell command window, execute the command `java -cp "xchart-demo-3.8.6.jar;xchart-3.8.6.jar" org.knowm.xchart.demo.XChartDemo`.
 
 E.g:
 ```sh
 cd /path/to/xchart-demo/jar/
-java -cp xchart-demo-3.8.5.jar:xchart-3.8.5.jar org.knowm.xchart.demo.XChartDemo
+java -cp xchart-demo-3.8.6.jar:xchart-3.8.6.jar org.knowm.xchart.demo.XChartDemo
 ```
 
 ## Running Demo - option 2 - building yourself

pom.xml

@@ -123,7 +123,7 @@
                     <plugin>
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-gpg-plugin</artifactId>
-                        <version>3.0.1</version>
+                        <version>3.1.0</version>
                         <executions>
                             <execution>
                                 <id>sign-artifacts</id>