Allow '=' as comparison operator

[kasadaamos]

The modified_lines condition allows only < or >.
I'd like to ask for an exact = option too.

The use case is that I want to allow different requirements for changes made by our automation, which should modify exactly two lines in a specific file.

There is no way to specify that accurately enough with < and >.

Thanks.

[asvoboda]

This sounds like a reasonable feature request. We'll happily review the change if you are interested in opening the PR.