The bind-mounted .git is owned by the host user but the dev
container runs as root, so git aborts with "dubious ownership"
and Go's automatic VCS stamping fails the build with:
error obtaining VCS status: exit status 128
Use -buildvcs=false to disable VCS stamping.
Production Dockerfiles are unaffected because they do not
bind-mount .git; they COPY source into the image and let Go
stamp normally.