Makefile: rm check and lint targets
Makefile: rm check and lint targets

The targets being removed were used by Travis CI, which is long gone.
Golangci-lint is now run by GHA CI without any help from the Makefile.

If a developer wants to run it locally,
they probably have it installed already, and typing

	golangci-lint run ./...

is relatively easy.

Signed-off-by: Kir Kolyshkin <3a017b8ddb3f9cf3e4a59978b004111bdeb97f08@gmail.com>

cpuguy83/go-md2man,cpuguy83/go-md2man