This fixes an issue where `make release` would fail to build the release
binaries, because `go build` would fail with `error obtaining VCS
status: exit status 128`.

This happens because `go build` in Go v1.18 and newer is invoking `git`
as part of the build process. However, due to
[CVE-2022-24765](https://github.blog/2022-04-12-git-security-vulnerability-announced/),
git v2.35.2 now requires that the current git directory for most
commands is owned by the user with which the `git` process is running.

Because our containerized build was running as `root` inside of the
container, git rightfully refused to work on a tree owned by a non-root
user. This commit fixes this issue by creating a release user with the
same UID/GID of the current user (assumed to be the user owning the
working directory), and running `make` with the permissions of that user
instead of running as root.

Signed-off-by: Sebastian Wicki <sebastian@isovalent.com>