Support later versions of Active Support + Ruby 3

[estromlund]

Hey all,

Thank you so much for merging #54! It looks like the changes included in that gem release broke our stack though. Would you please consider this fix, which should hopefully support all versions?

Problem

We're running Rails 6 so pinning to active_support ~> 4.2.7 gives us an incompatible gem issue since active_support is versioned with Rails (the current version is 7+). Since Rails depends on active_support, there is no way to support 4.2.x when Rails requires 6.x (or 7.x in the latest release).

Solution

Because the usage of active_support in this library is fairly limited, there seems to be no issue supporting later versions. The modifications required are in this PR.

I tested this PR on Ruby 2.7.5 and Ruby 3.0.3 and it seems to fix the issues across the board.

Please note that rexml is now specified as a dependency. Starting in Ruby 3, it was no longer included as a default gem. So the dependency was always there, but now we need to explicitly pull it in if needed.

[ckoegel]

Thanks @estromlund, we release on a fairly strict two week cadence, but I'll see if we can release this sooner so you don't have to wait until the 30th.

[estromlund]

@ckoegel No rush on our side, we're already pulling it in from a fork with the fix in place. Thank you for the quick responses on these issues - much appreciated!