Fix: Only upload test coverage for push events

Fixes #440.

Author: alexdewar

.github/workflows/ci.yml

@@ -40,7 +40,7 @@ jobs:
               --cov-report=xml
 
       - name: Upload coverage to Codecov
-        if: success() && (runner.os == 'Linux' && matrix.python-version == 3.9)
+        if: success() && (github.event_name == 'push' && runner.os == 'Linux' && matrix.python-version == 3.9)
         uses: codecov/codecov-action@v4
         with:
           fail_ci_if_error: true