Use debug.ReadBuildInfo for retrieving plugin version

[Semior001]

References to other Issues or PRs

closes #3022

Have you read the Contributing Guidelines?

Yes

Brief description of what is fixed or changed

Retrieve version of grpc-gateway and openapiv2 plugins via debug.ReadBuildInfo, upgraded go version to 1.18 (probably last part is not necessary)

Other comments

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[johanbrandhorst]

Sorry for the confusion, but is not what I meant. You've got the new files right, but I don't want them to be using an init function like this. Instead, please define a readVersion both in each of the go1.18 specific files and in some non-go1.18 specific files, so that the function is always available, then call the function from the main file like you did before. Does that make sense?

[Semior001]

Sorry for the confusion, but is not what I meant. You've got the new files right, but I don't want them to be using an init function like this. Instead, please define a readVersion both in each of the go1.18 specific files and in some non-go1.18 specific files, so that the function is always available, then call the function from the main file like you did before. Does that make sense?

Okay, got it. Please, check out the latest version of PR.

[johanbrandhorst]

Perfect, thank you!

[johanbrandhorst]

The bazel build is failing because the new files have not been added to the bazel definitions. Please run the file regeneration commands: https://github.com/grpc-ecosystem/grpc-gateway/blob/master/CONTRIBUTING.md#i-want-to-regenerate-the-files-after-making-changes.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.