feature request: option to not generate Bender.lock

[epsilon537]

I know, Bender.lock is the bee's knees, but for my particular use case, I don't need it.
I just use Bender to collect the sources from various components in a single repo. I use a build system where the build tree is separate from the source tree. No derived objects end up in the source tree, except, unfortunately, Bender.lock.
I can of course just write a wrapper script that deletes the Bender.lock file right after it has been generated, but that's very hack-y and I hate having scripts that run 'rm' commands in the source tree.
Having a -no_lock command line option would be great for my use case.

[micprog]

I don't see the use-case for this for general bender functionality, as almost all bender features (other than bender update which creates the lock, init, and completion) require the lockfile to exist, and will run the update code if it doesn't. There probably are some commands that don't need the complete update procedure to have run (i.e., config and vendor), but that is not currently implemented. Nonetheless, if you want to open a PR to support this, I can review and integrate it; you will likely need to add a script argument that prevents the following line from executing: https://github.com/pulp-platform/bender/blob/master/src/cmd/update.rs#L208