Add option to ignore assembly versions where comparing

[kkozmic]

When generating approvals file that contains type names the fully qualified name of types can change (common case is every build from TeamCity generating a new version number). This may lead to Approvals failing since at the text level, they are different.

An option to ignore/swap assembly version (version=x.x.x.x) would be helpful for those cases

[JakeGinnivan]

I think the output should not include the version number, each convention should make sure that it doesn't output any version of other data that may change

[kkozmic]

I agree for the default conventions.

This is also about providing helper API for people building their own to be able to use assembly qualified name if they wish so, but with version replacement