dev: enable testifylint linter

[alexandear]

The PR enables testifylint for this repo.

golangci-lint run

pkg/golinters/misspell_test.go:32:2: expected-actual: need to reverse actual and expected values (testifylint)
        assert.Equal(t, replacer.Replacements, expected)
        ^
pkg/result/processors/autogenerated_exclude_test.go:255:4: require-error: for error assertions use require (testifylint)
                        assert.EqualError(t, err, test.expected)
                        ^
pkg/result/processors/skip_files_test.go:52:2: require-error: for error assertions use require (testifylint)
        assert.Error(t, err)
        ^