add gitlab pipeline

.gitlab-ci.yml

+image: maven:3.9.9-eclipse-temurin-21-alpine
+
+variables:
+  MAVEN_DEPLOY_CLI_OPTS: "--no-transfer-progress -DskipTests"
+  MAVEN_CLI_OPTS: >-
+    -s .m2/ci_settings.xml --batch-mode
+    -Dmaven.plugin.validation=brief
+  DOCKER_HOST: tcp://docker:2375
+  DOCKER_TLS_CERTDIR: ""
+  DOCKER_DRIVER: overlay2
+
+services:
+  - docker:dind
+
+cache:
+  paths:
+    - .m2/repository/
+    - target/
+
+stages:
+  - build
+  - test
+  - publish
+
+build:
+  stage: build
+  script:
+    - mvn clean compile $MAVEN_CLI_OPTS
+  artifacts:
+    paths:
+      - target/*.jar
+
+test:
+  stage: test
+  script:
+    - mvn test $MAVEN_CLI_OPTS
+
+verify:
+  stage: test
+  script:
+    - mvn verify $MAVEN_CLI_OPTS
+
+snapshot-gitlab:
+  stage: publish
+  script:
+    - mvn deploy -Pgitlab-deploy $MAVEN_DEPLOY_CLI_OPTS $MAVEN_CLI_OPTS
+  only:
+    - main
+
+snapshot-nexus:
+  stage: publish
+  script:
+    - mvn deploy -Pnexus-deploy $MAVEN_DEPLOY_CLI_OPTS $MAVEN_CLI_OPTS
+  only:
+    - main
+
+release-gitlab:
+  stage: publish
+  script:
+    - mvn versions:set -DnewVersion=${CI_COMMIT_TAG}
+    - mvn deploy -Pgitlab-deploy $MAVEN_DEPLOY_CLI_OPTS $MAVEN_CLI_OPTS
+  rules:
+    - if: $CI_COMMIT_TAG
+
+release-nexus:
+  stage: publish
+  script:
+    - mvn versions:set -DnewVersion=${CI_COMMIT_TAG}
+    - mvn mvn deploy -Pnexus-deploy $MAVEN_DEPLOY_CLI_OPTS $MAVEN_CLI_OPTS
+  rules:
+    - if: $CI_COMMIT_TAG