Added a prepare job to documentation GH workflow

.github/workflows/documentation.yml

@@ -15,6 +15,31 @@ permissions:
   contents: read  #  to fetch code (actions/checkout)
 
 jobs:
+  prepare:
+    name: Prepare version strings
+    if: github.repository == 'openra/openra'
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Prepare environment variables
+        run: |
+          if [ "${{ github.event_name }}" = "push" ]; then
+            if [ "${{ github.ref_type }}" = "tag" ]; then
+              VERSION_TYPE=`echo "${GITHUB_REF#refs/tags/}" | cut -d"-" -f1`
+              echo "GIT_TAG=${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
+              echo "VERSION_TYPE=$VERSION_TYPE" >> $GITHUB_ENV
+            else
+              echo "GIT_TAG=bleed" >> $GITHUB_ENV
+              echo "VERSION_TYPE=bleed" >> $GITHUB_ENV
+            fi
+          else
+            VERSION_TYPE=`echo "${{ github.event.inputs.tag }}" | cut -d"-" -f1`
+            echo "GIT_TAG=${{ github.event.inputs.tag }}" >> $GITHUB_ENV
+            echo "VERSION_TYPE=$VERSION_TYPE" >> $GITHUB_ENV
+          fi
+    outputs:
+      git_tag: ${{ env.GIT_TAG }}
+      version_type: ${{ env.VERSION_TYPE }}
+
   wiki:
     name: Update Wiki
     if: github.repository == 'openra/openra'