Run actions on 3.10, lint on 3.9

.github/workflows/build.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9"]
+        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
         os: [macOS-latest, ubuntu-latest, windows-latest]
 
     steps:
@@ -32,7 +32,6 @@ jobs:
         run: make test
       - name: Lint
         run: make lint
-        if: ${{ matrix.python-version != '3.9' }}
       - name: Coverage
         run: codecov --token ${{ secrets.CODECOV_TOKEN }} --branch ${{ github.ref }}
         continue-on-error: true