* [CHANGE] Remove broken metrics collection #68
* [CHANGE] Remove use of cgroups #105
* [FEATURE] Add unit timestamp metrics #58

Build updates:
* Simplify build with CircleCI orb.
* Upgrade to Go 1.21.
* Switch form codespell to misspell linter.
* Enable revive linter.
* Removed unused func param.
* Remove unnecessary promu build flags.
* Move errcheck excludes inline.

Signed-off-by: SuperQ <superq@gmail.com>