Add partial support for ruby 3 / 3.1

[chaadow]

This basically replaces all URI.encode occurences with CGI.escape

As the maintainer of activestorage-openstack. this has made my test suite pass both on ruby 3.0 and 3.1 so the change should be enough for the storage component

It would be much appreciated if a release is made with this PR merged 🙏🏼

Fixes #522

[maciejpankanin]

I don't think CGI.escape is a good choice here since we need URL escaping. See https://stackoverflow.com/a/13059657/7998769.

I think using addressable gem would be safer.

[geemus]

I think the bigger question is whether any of these should keep / or not (ie it looks like some names might include this, which probably shouldn't be escaped but CGI would escape it). Can anyone speak more authoritatively on whether we should be concerned about this?