fix(etag): fix etag being noisy when no actual state has been changed

[aamkye]

Resolves:

• continual changes detected due to changing etag #796
• resource github_repository: etag: DiffSuppressFunc is for suppressing differences #910
• A way to hide certain expected changes from the "refresh" report ("Objects have changed outside of Terraform") hashicorp/terraform#28803
• Revert 654b4e5 #911
• fix(r/repository): suppress etag changes #909

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Before the change?

• ETag are shown in diff on almost every plan, even after apply just before the next plan.

After the change?

• ETag is hidden from output.

Pull request checklist

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• Yes
• No

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Disclaimer - I made the change according to my needs, please let me know if this should be extended to all/other resources.

[aamkye]

@kfcampbell could you look at this? :)

[kfcampbell]

@aamkye I can't accept a PR that modifies a vendored file, sorry. That would just be overwritten the next time dependencies are updated. I agree that this issue is super annoying but maybe we can find a more durable way around it.

[aamkye]

@kfcampbell, so if I understood correctly, first I need to make a change in vendor file but within vendor repo (https://github.com/hashicorp/terraform-plugin-sdk), and then adjust suppression functions?