Set env variable to project number

Author: antonwolfy

.github/workflows/build-sphinx.yml

@@ -106,7 +106,9 @@ jobs:
         working-directory: doc
 
       - name: Set a project number to current release
-        run: export PROJECT_NUMBER=$(git describe --tags --abbrev=0)
+        uses: trevorlloydelliott/set-environment-variables@v1.0.0
+        with:
+          PROJECT_NUMBER: "$(git describe --tags --abbrev=0)"
 
       # https://github.com/marketplace/actions/doxygen-action
       - name: Build backend docs