Update main_py_to_bitly.yml

Author: skysign

.github/workflows/main_py_to_bitly.yml

@@ -12,7 +12,7 @@
             fetch-depth: 2
         - name: get path of main.py
           run: |
-            echo "zero_length_string="" >> $GITHUB_ENV
+            echo "zero_length_string=\"\"" >> $GITHUB_ENV
             echo "path_of_main_py=$(git diff --name-only HEAD~1 HEAD | grep '/main\.py')" >> $GITHUB_ENV
         - name: Existing path of main.py
           if: ${{ env.zero_length_string }} == ${{ env.path_of_main_py }}