2.0.0

Required ruby version is now 3.0.0
Changed diff labels to include gem directory names
Fixed diff labels for /dev/null

1.2.2

Fix for Ruby 2.3 and Ruby 2.4

1.2.1

Fix bug introduced by 1.2.0 changes

1.2.0

Optimized #run for when the version of the gem to diff against is installed locally

1.1.0

Added version option

Use the version option to diff against a specific gem version. For example:
```
$ bundle diff GEMNAME --version 1.2.3
```
The option accepts RubyGem version requirements. For example:
```
$ bundle diff GEMNAME --version '~> 2'
```
Added help option

1.0.0

First version!