ci: Reduce checks run duplication

Author: dbanty

.github/workflows/checks.yml

@@ -4,7 +4,6 @@ on:
   push:
     branches: ["main"]
   pull_request:
-    # The branches below must be a subset of the branches above
     branches: ["main"]
 
 jobs:
@@ -26,11 +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