Remove explicit GitHub dependency from Gemfile

[marcotc]

I noticed that every time I ran bundle install in this repository, Bundler would take a second or two to fetch this gem:

$ bundle install
Fetching https://github.com/nixme/pry-nav.git

It seems like we introduced this GitHub dependency due to an incompatibility between our pry, debugger pry-nav, and the version of pry we used at the time.

Fast-forward a year, a new version pry-nav has been released that supports pry version < 13.

I've also unlocked the patch version from pry-stack_explorer, as there was a patch release since we last locked it.

The new versions are compatible with all our supported versions of Ruby.

[marcotc]

Rails CI issue has been fixed. PR is ready for review.

[ericmustin]

pry/pry-nav stuff lgtm, small question: will pry-stack_explorer work with jruby, and, is that required? I noticed this issue on their repo from 2017...should we be disabling on jruby?

pry/pry-stack_explorer#14 (comment)

[marcotc]

That's a good point @ericmustin. Now that JRuby support is fully merged I tried the pry development experience again, and I noticed that pry-stack_explorer installs but doesn't work correctly. I couldn't find any alternatives, so I just removed it from installing with JRuby for the time being.

[marcotc]

Build will fail because of Rails 6.1.

[ericmustin]

👍