This PR adds `golangci-lint` based on the configuration from
`coder/coder`
([here](https://github.com/coder/coder/blob/main/.golangci.yaml)) then
migrated to v2 using `golangci-lint migrate` plus the addition of few
more linters.
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Signed-off-by: Callum Styan <callumstyan@gmail.com>
