ci: Report coverage for all Python versions (#1936)

* Remove check to only report coverage to Codecov for the oldest Python
(Python 3.7) and newest (Python 3.10) tested and instead report
the coverage for all versions. The coverage flag for Codecov is
'unittests-${{ matrix.python-version }}' and so the Codecov report
will now show coverage for all versions and not just the 'bookend'
versions.

.github/workflows/ci.yml

@@ -59,7 +59,6 @@ jobs:
     - name: Report core project coverage with Codecov
       if: >-
         github.event_name != 'schedule' &&
-        (matrix.python-version == '3.7' || matrix.python-version == '3.10') &&
         matrix.os == 'ubuntu-latest'
       uses: codecov/codecov-action@v3
       with: