Add a nanoc filter for erubi

[Fjan]

Add a nanoc filter for Erubi

To do

The test runs but Rubocop flags the use of eval. Erb / Erubis / Erubi all need to use eval, and can never be run on untrusted input, so I would suggest suppressing the warning.

Related issues

nanoc/features#8
#1096

[denisdefreyne]

Update .rubocop to exclude the the Security/Eval check for this file:

Security/Eval:
  Exclude:
    - 'test/**/*.rb'
    - 'spec/**/*.rb'
    - 'lib/nanoc/base/entities/code_snippet.rb'
    - 'lib/nanoc/filters/erubi.rb'

[denisdefreyne]

Looks good! I’ll release this as part of Nanoc 4.7.

[denisdefreyne]

@Fjan I forgot to attribute you in the release notes for 4.7, but it’ll be rectified in the 4.7.1 release notes (see e753887). Sorry!

[Fjan]

Sure, no problem :-)