Use Github Actions instead of Circle CI

[khos2ow]

Prerequisites

Put an x into the box(es) that apply:

• This pull request fixes a bug.
• This pull request adds a feature.
• This pull request enhances existing functionality.
• This pull request introduces breaking change.

For more information, see the Contributing Guide.

Description

This PR replaces Circle CI config for Github Actions. The workflow actions defined are:

• build for verifying, testing and building PRs and master
• prerelease for preparing a pre-release tag and publishing the artifacts for it (every tags of v*.*.*-* pattern, e.g. v0.7.0-alpha)
• release for preparing a release tag and publishing the artifacts for it (for every tags of v*.*.*, such as v0.7.0)
• stale for automatic interaction with stale PRs and issues (to be added)

Issues Resolved

List any existing issues this pull request resolves.

Checklist

Put an x into all boxes that apply:

• I have read the Contributing Guidelines.

Tests

• I have added tests to cover my changes.
• All tests pass when I run make test.

Documentation

• My change requires a change to the documentation.
• I have updated the documentation accordingly.

Code Style

• My code follows the code style of this project.

[khos2ow]

@metmajer This PR is blocked by #115 and also Action needs to be enabled from the repository Settings page.