update artifact url in readme when merge.yml is run

.github/workflows/merge.yml

@@ -45,7 +45,46 @@ jobs:
           done
 
       - name: upload artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
+        id: artifact-upload
         with:
           name: merge-files
-          path: merge_output/
+          path: merge_output/
+
+      - name: get artifact url
+        run: |
+          IFS='/' read -ra REPO <<< "$GITHUB_REPOSITORY"
+          OWNER="${REPO[0]}"
+          REPO_NAME="${REPO[1]}"
+          echo "Owner: $OWNER"
+          echo "Repository: $REPO_NAME"
+          
+          RUN_ID=${{ github.run_id }}
+          ARTIFACT_ID=${{ steps.artifact-upload.outputs.artifact-id }}
+          ARTIFACT_URL="https://github.com/$OWNER/$REPO_NAME/actions/runs/$RUN_ID/artifacts/$ARTIFACT_ID"
+          echo "Artifact URL: $ARTIFACT_URL"
+          
+          echo "ARTIFACT_URL=$ARTIFACT_URL" >> $GITHUB_ENV
+          echo "OWNER=$OWNER" >> $GITHUB_ENV
+          
+      - name: update url in runner README 
+        run: |
+          start_delim="<!-- start-link -->"
+          end_delim="<!-- end-link -->"
+          
+          # remove current URL
+          sed -i "/$start_delim/,/$end_delim/d" README.md
+          
+          # add new URL
+          printf "$start_delim\n$ARTIFACT_URL\n$end_delim\n" >> README.md
+          
+      # merge script always runs on any PR, this ensures link is only updated after a PR is merged into SiEPIC
+      - name: commit and push changes to README if we are in SiEPIC repo
+        run: |
+          git diff
+          git config --local user.email "${{ github.actor }}@users.noreply.github.com"
+          git config --local user.name "${{ github.actor }}"
+          git add README.md
+          git commit -m "update README with new artifact url"
+          git push 
+        if: ${{ env.OWNER == 'SiEPIC'}}