Update .gitlab-ci.yml

.gitlab-ci.yml

@@ -17,6 +17,8 @@ validate: &validate
   stage: build
   script:
     - 'mvn $MAVEN_CLI_OPTS test-compile'
+  only:
+    - master
   image: maven:3.3.9-jdk-8
 # For merge requests do not `deploy` but only run `verify`.
 # See https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html
@@ -24,4 +26,6 @@ verify: &verify
   stage: test
   script:
     - 'mvn $MAVEN_CLI_OPTS verify'
+  only:
+    - master
   image: maven:3.3.9-jdk-8