github_actions: run python tox on commit / pull

Use github action ubuntu-22.04 environment to install tox and then run
all tox envs defined in the tox.ini

Change-Id: I7f91314a2b9cd276e63cf2158100795c6bfc8ff3

.github/workflows/unit_tests.yml

@@ -0,0 +1,28 @@
+name: Cloudbase-Init unit tests
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        python-version: ["3.8","3.9","3.10"]
+        architecture: ["x64"]
+
+    steps:
+    - name: Checkout cloudbase-init repository
+      uses: actions/checkout@v3
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v1
+      with:
+        python-version: ${{ matrix.python-version }}
+        architecture: ${{ matrix.architecture }}
+    - name: Install python3 tox
+      shell: bash
+      run: |
+        python3 -m pip install tox
+    - name: Run Cloudbase-Init unit tests with tox
+      shell: bash
+      run: |
+        tox run-parallel -e py3,pep8,cover,docs -v