Use python version 3.9 due to issues with pandas on 3.10 microsoft#17760

Author: karthiknadig

.github/actions/smoke-tests/action.yml

@@ -21,7 +21,7 @@ runs:
     - name: Install Python
       uses: actions/setup-python@v2
       with:
-        python-version: '3.x'
+        python-version: '3.9'
 
     - name: Pip cache
       uses: actions/cache@v2

.github/workflows/build.yml

@@ -85,7 +85,7 @@ jobs:
         # entry to lower the number of runners used, macOS runners are expensive,
         # and we assume that Ubuntu is enough to cover the UNIX case.
         os: [ubuntu-latest, windows-latest]
-        python: ['2.7', '3.x']
+        python: ['2.7', '3.9']
         test-suite: [ts-unit, python-unit, venv, single-workspace, multi-workspace, debugger, functional]
     steps:
       - name: Checkout

.github/workflows/pr-check.yml

@@ -105,13 +105,13 @@ jobs:
       - name: Install test requirements
         run: python -m pip install --upgrade -r build/test-requirements.txt
 
-      - name: Install debugpy wheels (python 3.8)
+      - name: Install debugpy wheels (python 3.9)
         run: |
           python -m pip install wheel
           python -m pip --disable-pip-version-check install -r build/debugger-install-requirements.txt
           python ./pythonFiles/install_debugpy.py
         shell: bash
-        if: matrix.test-suite == 'debugger' && matrix.python == 3.8
+        if: matrix.test-suite == 'debugger' && matrix.python == 3.9
 
       - name: Install debugpy (python 2.7)
         run: |