Bump setup-python action to v3

Author: Vladimir Safonkin

.github/workflows/python-builder.yml

@@ -131,7 +131,7 @@ jobs:
         working-directory: ${{ runner.temp }}/${{ env.ARTIFACT_NAME }}
 
       - name: Setup Python ${{ env.VERSION }}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: ${{ env.VERSION }}
           architecture: ${{ matrix.arch }}

.github/workflows/releases-validation.yml

@@ -18,7 +18,7 @@ jobs:
         python: [3.5.4, 3.6.7, 3.7.5, 3.8.1]
     steps:
     - name: setup-python ${{ matrix.python }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v3
       with:
         python-version: ${{ matrix.python }}