Cleanup build scripts

build.gradle

@@ -14,6 +14,11 @@ ext."signing.password" = project.hasProperty("signing.password") ? project.getPr
 ext."signing.secretKeyRingFile" = project.hasProperty("signing.secretKeyRingFile") ? project.getProperty('signing.secretKeyRingFile') : ("${System.properties['user.home']}${File.separator}.gnupg${File.separator}secring.gpg")
 ext.isReleaseVersion = !projectVersion.endsWith("SNAPSHOT")
 
+ext {
+    springBootVersion = '2.6.6'
+    servletVersion = '4.0.1'
+}
+
 version projectVersion
 group "org.graceframework.plugins"
 
@@ -29,8 +34,8 @@ repositories {
 }
 
 dependencies {
-    compileOnly "org.springframework.boot:spring-boot-autoconfigure:2.6.6"
-    compileOnly "javax.servlet:javax.servlet-api:4.0.1"
+    compileOnly "org.springframework.boot:spring-boot-autoconfigure:$springBootVersion"
+    compileOnly "javax.servlet:javax.servlet-api:$servletVersion"
     compileOnly "org.graceframework:grace-core:$graceVersion"
     compileOnly "org.graceframework:grace-web-common:$graceVersion"
 }