chore: Update dependencies and do a small refactor

[erazemk]

This commit updates all the Go dependencies to their latest versions, updates workflow files a bit and does a small refactor, such as fixing typos and following best practices.

grpc.DialContext still needs to be updated, but I don't have enough experience with it or with this tool to be confident that I properly used it (due to the changes in the name resolver or the state changes).

[erazemk]

Regarding the CLA, I'm waiting for a response from my employer on which version I should sign.
Employer signed the CLA.

[ahmetb]

Sorry I couldn't get to this timely, you might wanna rebase go.{mod,sum} from HEAD as they're auto-merged from dependabot bumps now.

[erazemk]

Sure @ahmetb, updated the code, so you can take a look again.

[ahmetb]

Sorry this got out of sync again. :(

[erazemk]

Our company switched away from grpc-health-probe, so I'm not sure it's worth me keeping this PR up to date with any changes. I guess if you review the PR and approve it (since there will not be any functional changes), then I can resolve the conflicts and immediately merge it. Otherwise it's probably easier if I just close it.

[stefanb]

@erazemk, this huge PR with too many unrelated / formatting changes was closed, but the meaningful changes were already included in merged

• refactor: go.mod entries reordered to standard #285
• refactor: replace usage of deprecated ioutil package with os package #284
• docs: updated readme #286

The remaining Go changes were cherry 🍒 picked for review / discussion into:

• main.go: leftovers from PR #242 #289

Thanks / Hvala!

[erazemk]

Hi @stefanb, thanks for doing what's necessary to get these changes including, and for me giving attribution in your PRs, I appreciate it.