Add a GitHub Action workflow with a test matrix

[gsmet]

@rvesse here is the promised GH Action build. Tested in my fork with success.

[gsmet]

I noticed the Travis build and pushed an adjustment with coveralls and things are not going well, I will have a closer look.

[coveralls]

Pull Request Test Coverage Report for Build 613

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 72.102%

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Totals
Change from base Build 608:	0.0%
Covered Lines:	5686
Relevant Lines:	7886

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💛 - Coveralls

[gsmet]

I think this is all ready. I haven't removed the Travis workflow as switching to GH Actions is just a suggestion. Let me know what you think of it.