Bump codecov/codecov-action from 5 to 6 in the github-actions group (#671)

Bumps the github-actions group with 1 update: [codecov/codecov-action](https://github.com/codecov/codecov-action).


Updates `codecov/codecov-action` from 5 to 6
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v5...v6)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/ci_tests.yml

@@ -133,7 +133,7 @@ jobs:
 
     - name: Upload coverage to Codecov
       if: github.repository == 'EMMC-ASBL/oteapi-core'
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v6
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         files: coverage.xml
@@ -145,7 +145,7 @@ jobs:
 
     - name: Upload strategies coverage to Codecov
       if: github.repository == 'EMMC-ASBL/oteapi-core'
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v6
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         files: strategies.xml
@@ -195,7 +195,7 @@ jobs:
 
     - name: Upload coverage to Codecov
       if: github.repository == 'EMMC-ASBL/oteapi-core'
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v6
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         files: coverage.xml
@@ -207,7 +207,7 @@ jobs:
 
     - name: Upload strategies coverage to Codecov
       if: github.repository == 'EMMC-ASBL/oteapi-core'
-      uses: codecov/codecov-action@v5
+      uses: codecov/codecov-action@v6
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
         files: strategies.xml