🔧 Ignore PyPy 3.7 test outcome in CI

This is supposed to be temporary until said interpreter is fixed
or upgraded to PyPy 3.8 as `pip-tools` is going to drop support for
Python 3.7 in the upcoming release.

.github/workflows/ci.yml

@@ -153,4 +153,5 @@ jobs:
       - name: Decide whether the needed jobs succeeded or failed
         uses: re-actors/alls-green@13b4244b312e8a314951e03958a2f91519a6a3c9
         with:
+          allowed-failures: pypy # FIXME: drop once updated to `pypy-3.8`
           jobs: ${{ toJSON(needs) }}