`$FILENAME` is unsafe to include in the globals because it modifies ARGV
and raises an error if it's a file that does not exist. This causes two
issues if rdbg used to debug a command with arguments.
 * when using rdbg the server will crash when running `info globals`, as
   it does not catch the error
 * when using a DAP client that requests globals before the debugged
   program was able to handle its arguments then the ARGV changes and
   the program will not do what's expected

Accepts {key=>value} style and {key: value} style Hash#inspect
proposed in https://bugs.ruby-lang.org/issues/20433#note-10

"1234" is too short and may be included in tempfile paths.

* Add changelog_uri to gemspec

Supported here: https://guides.rubygems.org/specification-reference/#metadata
Useful for running https://github.com/MaximeD/gem_updater

* Remove wrong comma

…ne_text

When debugging the issue related to ruby/irb#919,
I noticed that debugger tests don't respect the IRB version I specified
in the Gemfile. This is because console tests force override the RUBYOPT
env, which will remove the `-rbundler/setup` injected by bundler.

Further more, if tests use `run_rdbg` with the `rubyopt` option, the
RUBYOPT will be overridden yet again.

So in this commit I did 2 improvements:

1. `run_rdbg` should append instead of override RUBYOPT
2. If tests are executed with bundler, we also run the debugger in PTY
   process with bundler by appending `-rbundler/setup` to RUBYOPT

pointed out at #1123