Increase cpu/mem for kaniko builds

During the first few migrations we've seen a trend of jobs exiting with Killed due to going over their memory limit. Moving these jobs to k8s-high-freq resolved the issue due to increased default request/limit (1cpu, 5/10gb memory).

k8s-default runner defaults are .5 CPU, 500Mi/2Gi memory request/limit. I think 1cpu, 3/5gb mem will be a reasonable baseline and any more intensive jobs can increase as necessary.