Cleanup the golangci.yml file and enable more linters.
`pkg/spec` and `iopodman.io` is history. The vendor directory
is excluded by default. The dependencies dir was listed twice.
Fix the reported problems in `pkg/specgen` because that was also
excluded by `pkg/spec`.
Enable the structcheck, typecheck, varcheck, deadcode and depguard
linters.
[NO TESTS NEEDED]
Signed-off-by: Paul Holzinger <paul.holzinger@web.de>
78b419909b