SpringBoot Smoke tests with web.xml should use web-app version of 3.1

The latest version of eclipse complains with older versions with XSD errors. Upgrading the web-app value to 3.1 appears to fix things.

Comment From: izeye

This doesn't seem to be a user-facing enhancement, so it might be better to be labeled as "type: task".

Comment From: snicoll

I agree @izeye. I've flipped it back and the forward port issues were already using type: task.