Migrate Dockerfile to Bookworm (#26802)

[wangziao9]

I propose to cherry-pick this commit from mastodon/mastodon that updates the Dockerfile.

Reason:
I am trying to launch closed-social/mastodon on Ubuntu 20.04 and Docker version 27.0.3.
When trying to build an image out of the Dockerfile using docker build -t closed-social ., I get the following errors:

36.61 /opt/ruby/bin/ruby: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.34' not found (required by /opt/ruby/bin/ruby)
36.61 /opt/ruby/bin/ruby: /lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.35' not found (required by /opt/ruby/lib/libruby.so.3.2)
36.61 /opt/ruby/bin/ruby: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.33' not found (required by /opt/ruby/lib/libruby.so.3.2)
36.61 /opt/ruby/bin/ruby: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.32' not found (required by /opt/ruby/lib/libruby.so.3.2)
36.61 /opt/ruby/bin/ruby: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.34' not found (required by /opt/ruby/lib/libruby.so.3.2)
------
Dockerfile:19

Updating the Dockerfile according to the attached commit resolves this issue.