fix: invalid dependabot config

[ripecosta]

Why am I submitting this PR

The versioning-strategy was set to increase for both npm and github actions in #1055. However, the GitHub Actions package ecosystem does not support that options (docs), which caused this validation error when the change was merged. This PR fixes that error by removing the versioning-strategy option from the GH Actions package ecosystem settings.

Does it fix an existing ticket?

No.

Checklist

• [x] only relevant code is changed (make a diff before you submit the PR)
• [x] tests are included and pass: yarn test (see details here)
• [x] documentation is changed or added

[ripecosta]

@karellm Fix for an issue introduced by one of my earlier PRs.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 95.35%. Comparing base (5d8c198) to head (398b9ce). Report is 3 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1058 +/- ## ======================================= Coverage 95.35% 95.35% ======================================= Files 10 10 Lines 1918 1918 ======================================= Hits 1829 1829 Misses 89 89 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[Oersta1rdt]

Good