Add Python 3.6 back to hash verify CI (#2008)

Author: Andrew-Chen-Wang

.github/workflows/integration.yaml

@@ -36,7 +36,7 @@ jobs:
      strategy:
        max-parallel: 15
        matrix:
-         python-version: ['3.6','3.7', '3.8', '3.9', '3.10', 'pypy-3.7']
+         python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', 'pypy-3.7']
          test-type: ['standalone', 'cluster']
          connection-type: ['hiredis', 'plain']
      env:
@@ -80,7 +80,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10', 'pypy-3.7']
+        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', 'pypy-3.7']
     steps:
       - uses: actions/checkout@v2
       - name: install python ${{ matrix.python-version }}