feat: Expose bump level as output

[mdanish98]

No description provided.

[ricogu]

@mdanish98 , thanks for the PR

1. please use "bumpLevel" as the output as it clearly distinguish with the existing output "bumped"
2. please channel this output to the run time specific level actions , like in https://github.com/SAP/pull-request-semver-bumper/blob/main/.github/actions/version-bumping/maven/action.yml
3. please channel this output to the gateway action, in https://github.com/SAP/pull-request-semver-bumper/blob/main/action.yml
4. in the test pipeline(https://github.com/SAP/pull-request-semver-bumper/blob/main/.github/workflows/build-and-test.yml), lets add the check for this output

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[ricogu]

Resolved #30

[ricogu]

LGTM