gitserver: pre-built p4-fusion artifacts
Created by: keegancsmith
I was hoping all the improvements made around this script would result in much faster build times. It does, but with a very high variance. As such I've instead uploaded the p4-fusion binary to the sourcegraph-artifacts bucket. I don't suspect we will often change versions here so this seems like a good approach. Additionally the build script is quite robust now, so when we do bump the version it will be easy to build the new version.
I believe this complexity and cache is justified by the build times introduced to our CI for this step.
Test Plan: Built image locally. Also pushing to main dry run branch to exercise image building on CI.
docker build -t p4-fusion --target=p4-fusion .