Cancel in-progress CI workflows on push

[mdpiper]

This PR updates the test, test-notebooks, lint, and docs CI workflows to allow them to be canceled when a new push occurs. The workflows are then started for the newly-pushed changes.

I learned about this from https://github.com/landlab/landlab/pull/1971.

[coveralls]

Pull Request Test Coverage Report for Build 10411635230

Details

• 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 99.949%

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Totals
Change from base Build 10308645448:	0.0%
Covered Lines:	1945
Relevant Lines:	1946

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💛 - Coveralls