specify python version for publish process to avoid incompatible with pytest

Author: dothinking

.github/workflows/publish.yml

@@ -20,7 +20,7 @@ jobs:
   build:
 
     # The type of runner that the job will run on
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
@@ -30,7 +30,7 @@ jobs:
       - name: Set up Python 3.x
         uses: actions/setup-python@v1
         with:
-          python-version: '3.x'
+          python-version: '3.10'
 
       - name: Display Python version
         run: python -c "import sys; print(sys.version)"