Readme .yml config update

[thejonroberts]

Update the readme to use YAML.unsafe_load to parse regex values, load won't by default. I had the same issue as #106 , and this solved it. See this psych discussion.

Note: .yml regex values must be in format !ruby/regexp /\A[a-z0-9\-\:]+\z/ to be read as Regexp class. Not specific to this gem, but I can add a note below this if it is helpful.

[thejonroberts]

I have signed the CLA!

[thejonroberts]

@etiennebarrie what do you think of this readme change? Sorry for the ping, this has been up for 2 weeks.

[etiennebarrie]

Thank you!