Update buf.gen.yaml to use new buf plugins

[metalmatze]

Renovate bot is failing because the newer versions aren't available as the old custom plugins anymore.

[CLAassistant]

All committers have signed the CLA.

[maxbrunet]

@metalmatze this regex needs to be updated too :)

parca/renovate.json

Line 47 in 8123277

"# renovate: datasource=(?<datasource>.+?) depName=(?<depName>.+?)(?: (?:packageName)=(?<packageName>.+?))?(?: versioning=(?<versioning>.+?))?\\s*-?\\s*remote: ('|\")?.*:(?<currentValue>.+?)(-\\d+)?('|\")?\\s"