Updates on the release job/makefile cleanup

[cpanato]

Summary

• using go1.18 we dont need to pass some ldflags anymore, the only one is the git tag which there is an open issues in the go library for that (dont recall the number, but will find it)
• clean up of the makefile and update cosign image

Documentation

n/a

[codecov-commenter]

Codecov Report

Merging #914 (ae2c948) into main (25dbcf5) will decrease coverage by 0.14%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #914      +/-   ##
==========================================
- Coverage   48.25%   48.11%   -0.15%     
==========================================
  Files          62       62              
  Lines        5398     5398              
==========================================
- Hits         2605     2597       -8     
- Misses       2511     2517       +6     
- Partials      282      284       +2     

Impacted Files	Coverage Δ
pkg/types/alpine/v0.0.1/entry.go	54.20% <0.00%> (-2.53%)	⬇️
pkg/types/rekord/v0.0.1/entry.go	48.82% <0.00%> (-0.67%)	⬇️

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