dev: add flag for extra docker args

[herkolategan]

In order to support git alternates an additional volume must be supplied to the
bazel support docker. The TeamCity script already supplies a utility method
called run_bazel which supplies the volume to support git alternates.

This change allows for extra arguments to be passed via a command line argument
to the docker invocation that is utilised for cross builds by the dev utility.

Resolves: #101829

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is 

[rickystewart]

For dev we typically just use command-line arguments instead of environment variables. Any particular reason why we have not done that here?

[herkolategan]

My reasoning was that it seems the docker invocation could form part of multiple commands now and in the future, thus an environment variable would ensure being able to always supply additional arguments to the invocation. But that said, I'm not opposed to sticking to command-line arguments to keep things uniform.

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @smg260 and @srosenberg)

[herkolategan]

@rickystewart Updated my PR to take command-line arguments instead.

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @smg260 and @srosenberg)

[srosenberg]

Reviewed all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @rickystewart and @smg260)

[rickystewart]

LGTM. Consider bumping the version number in the top-level ./dev script so people pick up the change.

[herkolategan]

TFTR!
bors r=srosenberg,rickystewart

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)