Increase review-app workhorse cpu

What does this MR do?

Given that existing limit at 375m and p99 limit utilization is close to 1.0, increase review-app workhorse CPU:

• request to 400m
• limit to 600m

This should alleviate the readiness errors on this container. At the moment, healthcheck on this container is averaging at 5 seconds, close to the timeout value.

Screenshots

git@review-21087-cont-5cde2m-unicorn-999f74fc6-4rvmz:/$ time /scripts/healthcheck

real    0m4.676s
user    0m0.864s
sys     0m0.013s
git@review-21087-cont-5cde2m-unicorn-999f74fc6-4rvmz:/$ time /scripts/healthcheck

real    0m5.512s
user    0m0.996s
sys     0m0.014s
git@review-21087-cont-5cde2m-unicorn-999f74fc6-4rvmz:/$ time /scripts/healthcheck

real    0m6.800s
user    0m1.074s
sys     0m0.010s

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides