Updated gitlab ci to fix issue with jobs:compile:cache:paths that should be an array

Signed-off-by: Louis Vallat <louis@louis-vallat.xyz>

.gitlab-ci.yml

@@ -39,7 +39,8 @@ compile: &compile
   cache:
     key: "$CI_COMMIT_REF_NAME"
     policy: push
-    paths: .m2/repository
+    paths: 
+      - .m2/repository
 
 # Run tests
 test: &test
@@ -50,7 +51,8 @@ test: &test
   cache:
     key: "$CI_COMMIT_REF_NAME"
     policy: pull
-    paths: .m2/repository
+    paths: 
+      - .m2/repository
 
 package:
   image: maven:3.6.3-jdk-14