Try to make Travis work with pull requests again

build.gradle

@@ -29,7 +29,11 @@ if (System.getenv('TRAVIS') != null) {
     if (System.env.TRAVIS_TAG != "") {
         ext.jmeEngineVersion = "3.2.0-" + System.env.TRAVIS_TAG + "-SNAPSHOT"
     } else {
-        ext.jmeEngineVersion = "3.2.0-SNAPSHOT" // Use Beta 2 instead of 3.1.0-master-SNAPSHOT
+        if (System.env.TRAVIS_PULL_REQUEST == "false") {
+            ext.jmeEngineVersion = "3.2.0-SNAPSHOT" // Use Beta 2 instead of 3.1.0-master-SNAPSHOT
+        } else {
+            ext.jmeEngineVersion = "3.2.0-" + System.env.TRAVIS_PULL_REQUEST_BRANCH + "-pr-" + System.env.TRAVIS_PULL_REQUEST + "-SNAPSHOT"
+        }
     }
 } else {
     ext.jmeEngineVersion = "3.2.0-SNAPSHOT" // In case you build of the HEAD of 3.1, you need to change that to 3.1.0-SNAPSHOT again