* Revert "update protos (#8515)"
This reverts commit f094fd204a.
It appears that #8515 may have been generated with an out-of-date version of
either buf or the gogo plugin. using the latest versions (buf 1.4.0 and gogo
1.3.2) reverts those changes.
* Add a script to re-generate protos with the latest tools.
This script is just a wrapper for the Make rule, but it runs the build inside a
container with the latest versions of buf and gogo installed. This reduces the
chance that an out-of-date ambient installation on a developer machine will get
us outdated output.
