ci(code-coverage): Use codecov token to improve CI stability

[ChristophWurst]

Ref codecov/codecov-action#903

[ChristophWurst]

/backport to stable1.15

[backportbot-nextcloud]

The backport to stable1.15 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable1.15
git pull origin/stable1.15

# Create the new backport branch
git checkout -b fix/foo-stable1.15

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable1.15

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[GretaD]

test.yml on stable1.15 is completely different that's why it fails

[ChristophWurst]

/backport to stable2.2