doc: update example for external tools

build: try with Go 1.18

docs: mention Akvorado as an example

build: for gitlab, don't cache bin/

gocov will break if GOROOT becomes unavailable.

build: speed up linting by always using ./...

This is quite odd, but revive is super slow when providing many
directories. I suppose they are evaluated several times.

build: add a variable for generated file

For example, this could be used for protobuf stuff

build: reenable atomic mode for test coverage by default

Doc says:

    set: bool: does this statement run?
    count: int: how many times does this statement run?
    atomic: int: count, but correct in multithreaded tests;
            significantly more expensive.

build: fix GOBIN

It needs to be an absolute path. Should be why I was using CURDIR.

github: rename workflow file to match workflow name

build: use module basename for binary