Automate updates to AUR and brew-cask

[r2d4]

Automatically updates the AUR installer and pushes the new package.
Updates the brew installer and sends a PR to the brew package repo.

I've tested this as much as I can locally. I wasn't able to test to the actual PR curl request.

I think we can add this at the end of our release job.

[codecov-io]

Codecov Report

Merging #1642 into master will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1642      +/-   ##
==========================================
+ Coverage   38.62%   38.66%   +0.03%     
==========================================
  Files          51       51              
  Lines        2664     2664              
==========================================
+ Hits         1029     1030       +1     
+ Misses       1454     1453       -1     
  Partials      181      181

Impacted Files	Coverage Δ
pkg/minikube/kubeconfig/config.go	51.4% <0%> (+0.93%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c5becb3...a367be0. Read the comment docs.