Add check-latest functionality (#406)

.github/workflows/test-python.yml

@@ -172,3 +172,27 @@ jobs:
 
     - name: Run simple code
       run: ${{ steps.setup-python.outputs.python-path }} -c 'import math; print(math.factorial(5))'
+
+  check-latest:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        python-version: ["3.8", "3.9", "3.10"]
+    steps:
+      - uses: actions/checkout@v3
+      - name: Setup Python and check latest
+        uses: ./
+        with:
+          python-version: ${{ matrix.python-version }}
+          check-latest: true
+      - name: Validate version
+        run: |
+          $pythonVersion = (python --version)
+          if ("$pythonVersion" -NotMatch "${{ matrix.python }}"){
+            Write-Host "The current version is $pythonVersion; expected version is ${{ matrix.python }}"
+            exit 1
+          }
+          $pythonVersion
+        shell: pwsh