build(deps): bump codecov/codecov-action from 3 to 4

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 3 to 4.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v3...v4)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/gap.yml

@@ -78,7 +78,7 @@ jobs:
         with:
           GAP_TESTFILE: "tst/github_actions/extreme.g"
       - uses: gap-actions/process-coverage@v2
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
 
   test-cygwin:
     name: "cygwin / GAP master"
@@ -98,7 +98,7 @@ jobs:
           tar xf "${{ env.DIGRAPHS_LIB }}.tar.gz"
       - uses: gap-actions/run-pkg-tests@cygwin-v2
       - uses: gap-actions/process-coverage@cygwin-v2
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
 
   with-external-planarity-bliss:
     runs-on: "ubuntu-latest"