Skip deprecated functions unless -deprecated is given

[bobg]

This PR causes decouple to skip deprecated functions by default. This can be overridden with the new Checker.Deprecated option and -deprecated command-line flag.

[github-actions]

Modver result

This report was generated by Modver,
a Go package and command that helps you obey semantic versioning rules in your Go module.

This PR requires (at least) an increase in your module's minor version number.

checking Checker
  struct field Deprecated was added to github.com/bobg/decouple.Checker
    Minor

[coveralls]

Pull Request Test Coverage Report for Build 19978162802

Details

• 9 of 26 (34.62%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.8%) to 79.415%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
decouple.go	7	13	53.85%
cmd/decouple/main.go	2	13	15.38%

Totals
Change from base Build 19599657329:	-0.8%
Covered Lines:	733
Relevant Lines:	923

---

💛 - Coveralls