bump maven version in CI

.gitlab-ci.yml

@@ -31,7 +31,7 @@ test:frontend:
     - npm test
 
 .jdk_8_template: &jdk_8_definition
-  image: maven:3.6.0-jdk-8
+  image: maven:3.6.3-jdk-8
   services:
     - postgres:9.6
   stage: test
@@ -40,7 +40,7 @@ test:frontend:
     - mvn dependency:purge-local-repository -DmanualInclude="lcsb.mapviewer"
 
 .jdk_11_template: &jdk_11_definition
-  image: maven:3.6.0-jdk-11
+  image: maven:3.6.3-jdk-11
   services:
     - postgres:9.6
   stage: test
@@ -49,7 +49,7 @@ test:frontend:
     - mvn dependency:purge-local-repository -DmanualInclude="lcsb.mapviewer"
 
 .hsql_template: &hsql_definition
-  image: maven:3.6.0-jdk-11
+  image: maven:3.6.3-jdk-11
   stage: test
   coverage: '/(\d+.\d+) \% covered/'
   before_script:
@@ -312,7 +312,7 @@ test:backend:web:hsql:
   script: *test_backend_web_definition
 
 build_war:
-  image: maven:3.6.0-jdk-8
+  image: maven:3.6.3-jdk-8
   stage: build
   only:
     - tags
@@ -335,7 +335,7 @@ build_war:
     - cp web/target/*.war minerva.war
 
 test:dependency_conflict:
-  image: maven:3.6.0-jdk-8
+  image: maven:3.6.3-jdk-8
   stage: test
   script:
     - apt-get update
@@ -353,7 +353,7 @@ test:dependency_conflict:
     - test 0 = $conflicts
 
 test:code_validation:
-  image: maven:3.6.0-jdk-8
+  image: maven:3.6.3-jdk-8
   stage: test
   script:
     - apt-get update
@@ -554,7 +554,7 @@ test_deploy_with_db_without_superadmin_rights:
 
 
 .test_database_template: &test_database_definition
-  image: maven:3.6.0-jdk-8
+  image: maven:3.6.3-jdk-8
   stage: test
   script:
     - mvn -DskipTests=true clean install -pl persist -am