Replace `Fixnum` with `Integer`

Ruby 3 doesn't allow opening URLs with open

Bump to 3.4.3 (npm only)

rake convert[v3.4.1]

replace_division: balance parens

Bump to 3.4.2 (npm only)

package.json: node-sass -> sass

rake convert[v3.4.1]

handle math.div

Rakefile: require 'bundler/gem_tasks'

Bump bootstrap-sass to 3.4.1

rake convert[v3.4.1]

v3.4.0

Revert relative imports change

Test Rails app: Depend on sassc-rails