Support Targeting Go Versions For Staticcheck

[mneverov]

Is your feature request related to a problem? Please describe.
I'd like golangci-lint to support targeting go versions for staticcheck.
From go 1.15 release notes:
A TestMain function is no longer required to call os.Exit. If a TestMain function returns, the test binary will call os.Exit with the value returned by m.Run.

golangci-lint --version
golangci-lint has version 1.39.0 built from 9aea4aee on 2021-03-26T08:02:53Z

When staticcheck run as a separate binary with -go 1.15 there is no errors, when run via golangci-lint:
SA3000: TestMain should call os.Exit to set exit code (staticcheck) is reported.

Describe the solution you'd like
An option to configure go version for staticcheck.

[boring-cyborg]

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