Set minikube Kubernetes version to 1.21.5

[psschwei]

Currently, we are not setting a version for minikube (which as of now is defaulting to v1.22). As 1.22 might cause some problems, we should pin the version to 1.21.5 (currently the latest path version of 1.21).

/assign

[csantanapr]

What are the issues with 1.22?
I'm using 1.22 with minikube on MacOS

If there are issues with 1.22 I agree we can pin to 1.21 but open a new issue now to upgrade to 1.22 as soon the issues are resolved

[psschwei]

My bad... there were some issues with 1.22, but they were resolved in early September (PR). I'll update the PR to use v1.22