ci: setup github action workflow for testing

[faustbrian]

Setup lint, depcheck and unit testing as workflows for GitHub Actions.

What kind of change does this PR introduce?

• Bugfix
• Feature
• Refactor
• Performance
• Tests
• Build
• Documentation
• Code style update
• Continuous Integration
• Other, please describe:

Does this PR introduce a breaking change?

• Yes
• No

Does this PR release a new version?

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the develop branch, not the master branch
• All tests are passing
• New/updated tests are included

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

[codecov]

Codecov Report

Merging #1462 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1462   +/-   ##
========================================
  Coverage    41.41%   41.41%           
========================================
  Files          237      237           
  Lines         6616     6616           
  Branches      1299     1299           
========================================
  Hits          2740     2740           
  Misses        3646     3646           
  Partials       230      230

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[alexbarnsley]

@faustbrian there are failing things

[faustbrian]

Yeah, it's just the depcheck task which is unrelated to this PR. I'll send another PR to fix that issue.

[faustbrian]

@alexbarnsley