ci(gitlab): add release stage and job

.gitlab-ci.yml

@@ -7,6 +7,7 @@ workflow:
 
 stages:
   - test
+  - release
   - build
 
 variables:
@@ -34,6 +35,14 @@ lint dockerfile:
       changes:
         - Dockerfile
 
+release:
+  stage: release
+  image: docker.io/python:3.8-alpine
+  before_script:
+    - pip install --user --requirement requirements.ci.txt
+  script:
+    - semantic-release --verbosity=DEBUG publish
+
 build container image:
   stage: build
   image: