Fix concurrent for resolvers

[krupyansky]

Describe your PR and link to any relevant issues.

I have:

• Added tests covering the bug / feature (see testing)
• Updated any relevant documentation (see docs)

[coveralls]

coverage: 56.603% (-0.1%) from 56.704%
when pulling cc6e33b on krupyansky:bugfix/concurrent-for-resolvers
into dd41baf on 99designs:master.

[krupyansky]

@StevenACoffman I don't understand why stage "Format and Generate / fmt-and-lint (1.22) (pull_request)" failed

I make command "generate ./..." in root folder of project and commit and push cnanges. But I got fail...(

[UnAfraid]

@StevenACoffman I don't understand why stage "Format and Generate / fmt-and-lint (1.22) (pull_request)" failed

I make command "generate ./..." in root folder of project and commit and push cnanges. But I got fail...(

Run

go generate ./...; cd _examples; go mod tidy; go generate ./...; cd ..