* Merge RubyGems-3.5.6 and Bundler-2.5.6

* Merge RubyGems-3.5.7 and Bundler-2.5.7

* Merge RubyGems-3.5.8 and Bundler-2.5.8

* Partly reverted about https://github.com/rubygems/rubygems/pull/7483

* Merge RubyGems-3.5.9 and Bundler-2.5.9

https://github.com/rubygems/rubygems/commit/2720da2659

https://github.com/rubygems/rubygems/commit/fd2e71dfdb

https://github.com/rubygems/rubygems/commit/bb66253f2c

The `lock` command is specifically designed to manage the lockfile, so
running it should take precedence over any "frozen" setting.

Besides that, "frozen" is not specifically designed as "lockfile cannot
be updated" but as "installation of gems should be prevented if gemfile
is not in sync with the lockfile".

The lock command does not install any gems and preserves the property of
the lockfile being in sycn with its gemfile, so I think frozen should
not influence it.

The current behavior is quite confusing when frozen is set. On an app
where rubocop can get lockfile updates

```
$ bundle lock --update rubocop
Writing lockfile to /path/to/Gemfile.lock
```

Completely silent, it makes you think that it has written the lockfile,
but still no updates.

In verbose mode, it gives a bit more information, but still confusing
and unexpected, and does not change the lockfile:

```
$ bundle lock --update rubocop --verbose
Running `bundle lock --update "rubocop" --verbose` with bundler 2.4.20
Frozen, using resolution from the lockfile
Writing lockfile to /path/to/Gemfile.lock
```

With this commit, it updates the lockfile as expected.

https://github.com/rubygems/rubygems/commit/1d501ae8ea

https://github.com/rubygems/rubygems/commit/bc233af4d2

bundle lock --update can do everything that bundle update can do, but
it doesn't actually install gems. This is especially useful for
generating a lockfile on a machine that doesn't have the libraries
available to be able to build native extensions.

But, there was no parallel for bundle update --bundler. So let's add
one.

https://github.com/rubygems/rubygems/commit/7fc00bd2a5

  https://github.com/rubygems/rubygems/pull/5960

  Co-authored-by: David Rodríguez <deivid.rodriguez@riseup.net>