Update most Gradle dependencies to latest version.

- Do not update junit and jastadd-gradle yet
- Also use consistent long-form dependency specification

stub.org.openhab.core.scriptengine.action/build.gradle

@@ -7,8 +7,8 @@ sourceCompatibility = 1.8
 apply plugin: 'java'
 
 dependencies {
-    compile group: 'org.apache.logging.log4j', name: 'log4j-api', version: '2.11.1'
-    compile group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.11.1'
+    compile group: 'org.apache.logging.log4j', name: 'log4j-api', version: '2.11.2'
+    compile group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.11.2'
     testCompile group: 'junit', name: 'junit', version: '4.12'
     testCompile group: 'org.hamcrest', name: 'hamcrest-junit', version: '2.0.0.0'
 }