option to configure: containsMessage instead of matchMessage in deprecation-workflow.js?

[LalithaRajanala]

This is my first time opening an issue in ember. Will be very happy to provide more information if needed :)

I love ember-cli-deprecation-workflow addon and I want to use it to handle all the errors where the error message includes certain string. Right now my way to work around it is to say
matchMessage: / This is a deprecated message .* /

Instead, can we have an option to say containsMessage: 'This is deprecated message' ?
This will help me define a string in the message instead of always defining a regex to see if substring is present in a string.

Thank you!