Unable to install Ruby 2.1.5 on Ubuntu 22.04

Question

I need to work on a legacy project which the ruby version in it doesn't seem to be in the rvm repository for my release of Ubuntu (22.04).

when I try: rvm install 2.1.5, I get:

No binary rubies available for: ubuntu/22.04/x86_64/ruby-2.1.5.
Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
Checking requirements for ubuntu.
Removing undesired packages: libssl-dev

And then it prompts my password to remove libssl-dev, which I'm wary of doing so as I'm worried it might affect my other installations.

looking into the rvm mount help page, I found instructions that might help me:

You can specify the full url to the binaries:

    rvm mount -r https://rvm.io/binaries/ubuntu/12.04/x86_64/ruby-1.9.3-p194.tar.bz2

It is also possible to download from different url with a name to use:

    rvm mount -r https://some.server/my_ruby-1.9.3-p194.tar.bz2 ruby-1.9.3-p194

Note that the packaged ruby must be using exactly the name that was given as second parameter.

I looked for the official Ruby 2.1.5 release and noticed there's a link with the same packaging (.tar.bz2) as the ones in the rvm repository.

Still, Upon running:

rvm mount -r https://cache.ruby-lang.org/pub/ruby/2.1/ruby-2.1.5.tar.bz2 ruby-2.1.5

I got:

https://cache.ruby-lang.org/pub/ruby/2.1/ruby-2.1.5.tar.bz2 - #configure
Unknown ruby interpreter version (do not know how to handle): https://cache.ruby-lang.org/pub/ruby/2.1/ruby-2.1.5.tar.bz2.
Found remote file 
ruby-2.1.5 - #download
No remote url detected for ruby-2.1.5.