Add python v3.10 to the test suite

Version 3.10 has been out a while so lets make sure the tests pass for
it.

Author: php1ic

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9, 3.10]
 
     steps:
     - uses: actions/checkout@v2
@@ -29,7 +29,7 @@ jobs:
       run: |
         coverage run -m pytest -v && coverage xml
     - name: Upload coverage to Codecov
-      if: ${{ matrix.python-version == '3.9' }}
+      if: ${{ matrix.python-version == '3.10' }}
       uses: codecov/codecov-action@v1
       with:
         token: ${{ secrets.CODECOV_TOKEN }}