ci: Test on Python 3.10 [#468, #470]

Author: dbanty

.github/workflows/checks.yml

@@ -4,17 +4,15 @@ on:
   push:
     branches: ["main"]
   pull_request:
-    # The branches below must be a subset of the branches above
     branches: ["main"]
 
 jobs:
   test:
     strategy:
       matrix:
-        python: [ 3.7, 3.8, 3.9 ]
+        python: [ "3.7", "3.8", "3.9", "3.10" ]
         os: [ ubuntu-latest, macos-latest, windows-latest ]
     runs-on: ${{ matrix.os }}
-
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python
@@ -27,11 +25,11 @@ jobs:
         path: .venv
         key: ${{ runner.os }}-${{ matrix.python }}-dependencies-${{ hashFiles('**/poetry.lock') }}
         restore-keys: |
-          ${{ runner.os }}-${{ matrix.python }}-dependencies-v2
+          ${{ runner.os }}-${{ matrix.python }}-dependencies
     - name: Install dependencies
       run: |
         pip install poetry
-        poetry config virtualenvs.in-project true
+        python -m venv .venv
         poetry run python -m pip install --upgrade pip
         poetry install