Revert remove gradle cache

Author: upgle

.travis.yml

@@ -44,14 +44,14 @@ notifications:
 
 # specific cache configuration for gradle based builds
 # see: https://docs.travis-ci.com/user/languages/java/#caching
-#before_cache:
-#  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
-#  - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
-#
-#cache:
-#  directories:
-#    - $HOME/.gradle/caches/
-#    - $HOME/.gradle/wrapper/
+before_cache:
+  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
+  - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
+
+cache:
+  directories:
+    - $HOME/.gradle/caches/
+    - $HOME/.gradle/wrapper/
 
 before_install:
   - sudo systemctl stop epmd.socket epmd.service