Update _integration_test.yml

Author: haiyang679

.github/workflows/_integration_test.yml

@@ -10,6 +10,7 @@ on:
         description: "From which folder this pipeline executes"
 
 env:
+  PYTHON_VERSION: "3.9"
   POETRY_VERSION: "1.7.1"
 
 jobs:
@@ -64,4 +65,4 @@ jobs:
             
             # grep will exit non-zero if the target message isn't found,
             # and `set -e` above will cause the step to fail.
-            echo "$STATUS" | grep 'nothing to commit, working tree clean'
+            echo "$STATUS" | grep 'nothing to commit, working tree clean'