Fix linter warnings for healthcheck client
internal/gitlabnet/healthcheck/client.go:44:23: Error return value of `resp.Body.Close` is not checked (errcheck)
internal/gitlabnet/healthcheck/client.go:1:1: package-comments: should have a package comment (revive)
internal/gitlabnet/healthcheck/client.go:17:6: exported: exported type Client should have comment or be unexported (revive)
internal/gitlabnet/healthcheck/client.go:22:6: exported: exported type Response should have comment or be unexported (revive)
internal/gitlabnet/healthcheck/client.go:29:1: exported: exported function NewClient should have comment or be unexported (revive)
internal/gitlabnet/healthcheck/client.go:38:1: exported: exported method Client.Check should have comment or be unexported (revive)
internal/gitlabnet/healthcheck/client.go:32:15: ST1005: error strings should not be capitalized (stylecheck)
Contributes to #737 (closed)
Edited by Ash McKenzie