Disable brew cask updater

Version bump to v1.5.2

Allow CPU count check to be disabled using --force

Make network validation friendlier, especially to corp networks

Avoid the s3 and gcs protocol handlers in go-getter

service: fix --url mode, add integration tests

Fix pod list retry, reset start timer

Automatically install periodic cleanup script on macOS and Linux

Improve parallel start scheduling and autoset parallelism

Improve reliability of TestStartStop with none driver

CI: kill VboxHeadless processes, move load warning until after cleanup

Refactor command runner interface, allow stdin writes