When using gitlab-ci on a java+maven project; the maven artifacts are not cached. They are getting downloaded every-time.

I have deployed the gitlab-runner as kubernetes.

And the build time logs show

Creating cache edu-erp...
.m2/repository/: found 761 matching files          
No URL provided, cache will be not uploaded to shared cache server. Cache will be stored only locally. 

.gitlab-ci.yml

image: maven:latest

variables:
  MAVEN_CLI_OPTS: "--batch-mode --errors --fail-at-end --show-version"
  MAVEN_OPTS: "-Djava.awt.headless=true -Dmaven.repo.local=./.m2/repository"

cache:
  paths:
    - ./.m2/repository
  # keep cache across branch
  key: "$CI_BUILD_REF_NAME"


stages:
  - build
  - test

build:
  stage: build
  cache:
    key: edu-erp
    paths:
      - .m2/repository/
  script:
    - "mvn clean compile $MAVEN_CLI_OPTS"
  artifacts:
    paths:
      - target/

test:
  stage: test
  cache:
    key: edu-erp
  script:
    - "mvn test $MAVEN_CLI_OPTS"

The cache should be available across builds.