update PR correctly if new breaking changes are found

Author: ezhang6811

.github/workflows/nightly-build.yml

@@ -26,21 +26,6 @@ jobs:
         fetch-depth: 0
         token: ${{ secrets.GITHUB_TOKEN }}
 
-    - name: Configure git and create branch
-      run: |
-        git config --local user.email "[email protected]"
-        git config --local user.name "GitHub Action"
-    
-    - name: Check out dependency update branch
-      run: |
-        if git ls-remote --exit-code --heads origin "$BRANCH_NAME"; then
-          echo "Branch $BRANCH_NAME already exists, checking out..."
-          git checkout "$BRANCH_NAME"
-        else
-          echo "Branch $BRANCH_NAME does not exist, creating new branch..."
-          git checkout -b "$BRANCH_NAME"
-        fi
-    
     - name: Set up Python
       uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c #v6.0.0
       with:
@@ -62,6 +47,21 @@ jobs:
         OTEL_CONTRIB_VERSION: ${{ steps.get_versions.outputs.otel_contrib_version }}
       run: python scripts/find_breaking_changes.py
 
+    - name: Configure git and create branch
+      run: |
+        git config --local user.email "[email protected]"
+        git config --local user.name "GitHub Action"
+    
+    - name: Check out dependency update branch
+      run: |
+        if git ls-remote --exit-code --heads origin "$BRANCH_NAME"; then
+          echo "Branch $BRANCH_NAME already exists, checking out..."
+          git checkout "$BRANCH_NAME"
+        else
+          echo "Branch $BRANCH_NAME does not exist, creating new branch..."
+          git checkout -b "$BRANCH_NAME"
+        fi
+    
     - name: Update dependencies
       env:
         OTEL_PYTHON_VERSION: ${{ steps.get_versions.outputs.otel_python_version }}
@@ -84,6 +84,7 @@ jobs:
         fi
     
     - name: Create or update PR
+      if: steps.check_changes.outputs.has_changes == 'true'
       run: |
         PR_BODY="Automated update of OpenTelemetry dependencies.