Fixed python version pinning issue on colab.yml gha. (#5843)

.github/workflows/colab.yml

@@ -31,7 +31,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v2
       with:
-        python-version: 3.9.9
+        python-version: 3.9.x
     - uses: actions/setup-dotnet@v1
       with:
         dotnet-version: '6.0.x'