Update Nokogiri & Ruby version

[etherz10]

Closes #120

While bumping the minimum Nokogiri version I ran into the following error which required me to update the minimum required Ruby version for the Gem.

Given 3.0.x is already EOL I think stopping 2.x is fine?

Fetching gem metadata from https://rubygems.org/.
Resolving dependencies...
Bundler could not find compatible versions for gem "ruby":
  In Gemfile:
    ruby

    amazing_print was resolved to 1.6.0, which depends on
      ruby (>= 2.5.0)

    nokogiri (~> 1.16.7) was resolved to 1.16.7, which depends on
      ruby (>= 3.0.0)

[aburgel]

Came looking for a fix for this issue too. Updating nokogiri will certainly fix this, but I think the underlying cause is that the Gemfile.lock is included in the gem, which is not necessary.

The Gemfile.lock is not committed to the repo, so it looks like when building the gem, the lock file gets included incidentally.

A common practice is to use the list of committed files as filter for what's included in the gem. That would fix this issue and also keep out other unintended files.

You'd do something like this in the gemspec: https://github.com/rubygems/rubygems/blob/master/bundler/lib/bundler/templates/newgem/newgem.gemspec.tt#L28-L36

[HarlemSquirrel]

Yeah let's do it. Thanks!

[etherz10]

@HarlemSquirrel Any ETA on a RubyGems release?

[HarlemSquirrel]

Don't have time this week myself but maybe @paddor has some time

[paddor]

Yeah I can look into this.

[paddor]

After some hurdles, this is now released in v1.7.2.