Isolate dependency tests from GitPython pytest options

Running pytest below gitdb or smmap still discovers GitPython's root
configuration. Its coverage addopts target the git package, which is not the
package under test and caused the new dependency matrix jobs to fail.

Clear inherited addopts for those jobs so each imported project runs its own
test suite without GitPython-specific coverage arguments.

Author: codex

.github/workflows/dependencies.yml

@@ -36,7 +36,7 @@ jobs:
     - name: Test
       run: |
         if test "${{ matrix.project }}" = gitdb; then
-          GITDB_TEST_GIT_REPO_BASE="$(git rev-parse --git-common-dir)" pytest -v gitdb/gitdb/test
+          GITDB_TEST_GIT_REPO_BASE="$(git rev-parse --git-common-dir)" pytest -o addopts= -v gitdb/gitdb/test
         else
-          pytest -v smmap/smmap/test
+          pytest -o addopts= -v smmap/smmap/test
         fi