Cache pyproject.toml

ci/deploy_pypi.yml

 deploy_pypi:
   stage: deploy
   script:
+    - if [ $CI_COMMIT_REF_NAME = master ]; then
+       poetry version $(poetry version | cut -d" " -f2)+$(date +%s).${CI_COMMIT_SHORT_SHA} ;
+      elif [ x$CI_OMMIT_REF_NAME = x$CI_COMMIT_TAG ]; then
+       if ! [ "$(poetry version | cut -d" " -f2)" = $CI_COMMIT_REF_NAME ]; then
+        echo "Package version does not match tag. Aborting build of tag!" >/dev/fd/2 ;
+        exit 1 ;
+       fi ;
+      fi
     - if [ $CI_COMMIT_REF_NAME = master ]; then
        poetry publish -r gitlab ;
       elif [ x$CI_OMMIT_REF_NAME = x$CI_COMMIT_TAG ]; then