Use metasploit-yard

MSP-11354

Use `metasploit-yard` for `rake yard`

# Pre-verification Steps
- [ ] Merge https://github.com/rapid7/metasploit-version/pull/2

# Verification Steps

## MRI
- [x] `rvm use ruby-2.1@metasploit-version`
- [x] `rm Gemfile.lock`
- [x] `bundle install`

### Cucumber
- [x] `rake cucumber`
- [x] VERIFY no failures

### Specs
- [x] `rake spec`
- [x] VERIFY no failures

### YARD
- [x] `rake yard`
- [x] VERIFY no warnings
- [x] VERIFY no undocumented objects

## JRuby
- [x] `rvm use jruby@metasploit-version`
- [x] `rm Gemfile.lock`
- [x] `bundle install`

### YARD
- [x] `rake yard`
- [x] VERIFY no warnings
- [x] VERIFY no undocumented objects

# Post-merge Steps

Perform these steps prior to pushing to master or the build will be broke on master.

## Version
- [ ] Edit `lib/metasploit/version/version.rb`
- [ ] Remove `PRERELEASE` and its comment as `PRERELEASE` is not defined on master.

## Gem build
- [ ] gem build *.gemspec
- [ ] VERIFY the gem has no '.pre' version suffix.

## RSpec
- [ ] `rake spec`
- [ ] VERIFY version examples pass without failures

## Commit & Push
- [ ] `git commit -a`
- [ ] `git push origin master`

# Release

Complete these steps on DESTINATION

## `VERSION`

### Incompatible changes

`MINOR` has already been incremented due to the incompatible removal of `Metasploit::Version.root` in favor of using `Gem::Specification#gemdir`.

## JRuby
- [ ] `rvm use jruby@metasploit-version`
- [ ] `rm Gemfile.lock`
- [ ] `bundle install`
- [ ] `rake release`

## MRI Ruby
- [ ] `rvm use ruby-2.1@metasploit-version`
- [ ] `rm Gemfile.lock`
- [ ] `bundle install`
- [ ] `rake release`