chore(workflow): migrate release tagging to github actions

[akhilerm]

Why is this PR required? What issue does it fix?: The PR migrates the release tagging process from travis to github actions as per this issue.

What this PR does?:

• add downstream tagging to release
• remove travis file
• update build status badge

Does this PR require any upgrade changes?:

If the changes in this PR are manually verified, list down the scenarios covered and commands you used for testing with logs:

Any additional information for your reviewer?: Mention if this PR is part of any design or a continuation of previous PRs

• GR_TOKEN secret needs to be added to the repo before merging
• travis app integration can be removed from the repository
• Dependent on #86

Checklist:

• [ ] Fixes #
• [x] PR Title follows the convention of <type>(<scope>): <subject>
• [ ] Has the change log section been updated?
• [ ] Commit has unit tests
• [ ] Commit has integration tests
• [ ] (Optional) Are upgrade changes included in this PR? If not, mention the issue/PR to track:
• [ ] (Optional) If documentation changes are required, which issue on https://github.com/openebs/openebs-docs is used to track them:

[akhilerm]

@kmova Can you add the GR_TOKEN to this repository