Update .gitlab-ci.yml

cache:

  paths:

    - .m2/repository/

    - target/

build:

  stage: build

  script:

    - mvn $MAVEN_CLI_OPTS compile

test:

  stage: test

  script:

    - mvn $MAVEN_CLI_OPTS test

    - "cat target/site/jacoco/index.html"

deploy:

  stage: deploy

  script:

    - mvn $MAVEN_CLI_OPTS deploy