[CD] Release on PyPI only on tags

• Have been removed because env var wasn’t shared wth non-protected tags
• https://docs.gitlab.com/ee/ci/variables/#protected-environment-variables

.gitlab-ci.yml

@@ -103,6 +103,7 @@ release:
     - make build
     - make deploy PYPI_LOGIN=${PYPI_LOGIN} PYPI_PASSWORD=${PYPI_PASSWORD}
   only:
+    - tags
     - master
 
 release_test: