Update BuildMultiplatform.yml

Author: juraj-hrivnak

.github/workflows/BuildMultiplatform.yml

@@ -74,9 +74,9 @@ jobs:
 
           cat PROJECTS_DIFF.md >> $GITHUB_STEP_SUMMARY
 
-          diff=$(< PROJECTS_DIFF.md)
-          diff=$(echo $diff | sed -r 's/\\\\n/\\n/g') # Fix new lines
-          diff >> "$GITHUB_OUTPUT"
+          output_diff=$(< PROJECTS_DIFF.md)
+          output_diff=$(echo $output_diff | sed -r 's/\\\\n/\\n/g') # Fix new lines
+          output_diff >> "$GITHUB_OUTPUT"
 
       - name: Send Discord message
         uses: "hugoalh/send-discord-webhook-ghaction@5af9cbe30a2a19e7ce18853012ef55487c985954" # 6.0.2