[NP-412] Builds custom proxy based on v2.294#222

reedflinch wants to merge 1 commit intoupstream/v2.294.0personio/linkerd2-proxy:upstream/v2.294.0from

v2.294.0-light-metricspersonio/linkerd2-proxy:v2.294.0-light-metricsCopy head branch name to clipboard