Remove pytest<8 pin in CI test workflow

Author: ianthomas23

.github/workflows/test.yml

@@ -69,7 +69,7 @@ jobs:
       run: |
         python -m pip install --only-binary ':all:' --upgrade pip setuptools wheel build
         python -m pip install --only-binary ':all:' --no-binary curio --upgrade -e .[${{ matrix.deps }}]
-        python -m pip install --only-binary ':all:' --upgrade check-manifest pytest-cov  'pytest<8'
+        python -m pip install --only-binary ':all:' --upgrade check-manifest pytest-cov pytest
     - name: Install and update Python dependencies (dev?)
       if: ${{ contains( matrix.python-version, 'dev' ) }}
       run: |