Enable more go linters [ready to split]

[xoxys]

Supersedes: #977

[woodpecker-bot]

Deployment of preview was successful: https://woodpecker-ci-woodpecker-pr-2960.surge.sh

[xoxys]

I'm a bit confused about how pre-commit is handling golangci-lint. While make lint still returns a lot of errors (PR not ready yet), pre-commit seems to be happy. Any idea @pat-s?

[xoxys]

Some remaining issues where I would like to get some input:

1. Why is != 2 correct here? Would like to document what 2 means and why it is the intended value.

server/forge/github/github.go:493:22: mnd: Magic number: 2, in <condition> detected (gomnd)
		if len(matches) != 2 {
		                   ^

2. Why 8 bytes? Would like to document why it is the intended value.

pipeline/multipart/reader.go:55:21: mnd: Magic number: 8, in <argument> detected (gomnd)
	out, _ := buf.Peek(8)
	                   ^

3. Why is < 2 correct here? Would like to document what 2 means and why it is the intended value.

pipeline/backend/docker/convert.go:125:19: mnd: Magic number: 2, in <condition> detected (gomnd)
		if len(parts) < 2 {
		                ^

pipeline/backend/docker/convert.go:152:19: mnd: Magic number: 2, in <condition> detected (gomnd)
		if len(parts) < 2 {
		                ^

4. If the goal is to get seconds from the given duration, would it be better to use time.Duration(cf.timeout.Seconds())?

server/forge/configFetcher.go:64:30: Multiplication of durations: `time.Second * cf.timeout` (durationcheck)
		files, err = cf.fetch(ctx, time.Second*cf.timeout, strings.TrimSpace(cf.configPath))
		                           ^

5. Why is <= 3 correct here? Would like to document what 3 means and why it is the intended value.

pipeline/shared/replace_secrets.go:23:18: mnd: Magic number: 3, in <condition> detected (gomnd)
		if len(old) <= 3 {
		               ^

6. Is it acceptable to not exec the defer function in this case, or do we need to refactor this part?

cmd/server/server.go:154:4: exitAfterDefer: log.Fatal will exit, and `defer func(){...}(...)` will not run (gocritic)
			log.Fatal().Err(err).Msg("failed to create web engine")

[xoxys]

Thanks! Will take care.

[6543]

in that case I'll reopen so it dont get deleted and the pull remains as TODO

[qwerty287]

Github never deletes code (except on force pushes) I think. The commits and PR diff should always be available, also on PR close/branch deletion.

[xoxys]

I've added dedicated PRs for all missing linters. Closing again.