Replacing Travis with Github actions

[iwankgb]

Important notes:

• I had to update go.mod and go.sum in tools/ - I wasn't able to run make generate otherwise
• goreleaser does not support gomips key in the configuration
• I got rid of time in Makefile to support builds on Windows.

I decided to extend builds to Windows and MacOS but:

• tests on Windows fail miserably
• tests on MacOS timeout on Go 1.14 (sometimes)

Release build was tested for Docker and Github releases. I was not able to test Homebrew. Secrets must be set for hub.docker.com (GOLANGCI_LINT_DOCKER_TOKEN) and Github (GOLANGCI_LINT_TOKEN) authentication

Fixes #1039, supersedes #1054

[iwankgb]

@ernado you may need to check some configuration options for the repository to enable Github Actions.

[ernado]

Oh, great job!

Can you please leave Travis for deploy script?
We are running goreleaser on version tag and I'm not sure that porting to actions is trivial.

[iwankgb]

I have already ported and tested it - see PR description.

[ernado]

Oh, now I see.

@jirfag PTAL, seems like we should add secrets in settings.
https://help.github.com/en/actions/configuring-and-managing-workflows/creating-and-storing-encrypted-secrets

[iwankgb]

There will be one more for Homebrew but I have no experience with the tool and I have no idea how to authenticate.

[jirfag]

cool, thank you!
I've added all GitHub secrets, so we can merge it

[jirfag]

let's remove 1.12 please to speed up CI like in #1060 . And the same for unix

[jirfag]

what's wrong with that?

[jirfag]

I can fix and check brew myself