ci: add automatic release

.gitlab-ci.yml

+---
+# Automatic release creation
+# TODO: Lint check for arduino
+# TODO: Arduino-build
+
+# https://docs.gitlab.com/ee/user/project/releases/release_cicd_examples.html
+release_job:
+  stage: release
+  image: registry.gitlab.com/gitlab-org/release-cli:latest
+  rules:
+    - if: $CI_COMMIT_TAG   # Run this job when a tag is created
+  script:
+    - echo "running release_job"
+  release:
+    tag_name: '$CI_COMMIT_TAG'
+    name: 'Release $CI_COMMIT_TAG'
+    description: 'Automatic release for $CI_COMMIT_TAG.'