Update upstream_sync.yml

.github/workflows/upstream_sync.yml

@@ -15,10 +15,17 @@ jobs:
 
       - name: Get latest upstream release
         run: |
-              echo "RAW_RELEASE_TAG=$(curl -L \
-              -H "Accept: application/vnd.github+json" \
-              https://api.github.com/repos/joernio/joern/releases/latest | jq -r .name)" >> $GITHUB_ENV
-              echo "LATEST_TAG=$(${{ env.RAW_RELEASE_TAG }} | sed 's/[v]//g' | sed 's/[.]/-/g' )" >> $GITHUB_ENV
+              # Fetch the latest release tag from the GitHub API
+              RAW_RELEASE_TAG=$(curl -L \
+                -H "Accept: application/vnd.github+json" \
+                https://api.github.com/repos/joernio/joern/releases/latest | jq -r .name)
+              
+              # Process the tag to create the desired format
+              LATEST_TAG=$(echo "$RAW_RELEASE_TAG" | sed 's/^v//' | sed 's/\./-/g')
+              
+              # Export to GitHub environment variables
+              echo "RAW_RELEASE_TAG=$RAW_RELEASE_TAG" >> $GITHUB_ENV
+              echo "LATEST_TAG=$LATEST_TAG" >> $GITHUB_ENV
 
       - name: Create tag branch and merge upstream
         run: |