AlertOnUnexpectedContentTypes.js reports false positive for application/grpc header

[hideintheclouds]

Due to the fact that the current script does not include support for application/grpc.* it will report that the content-type is unexpected.

The fix is to check against all possible header types that could include application/grpc

AlertOnUnexpectedContentTypes.js

[kingthorin]

I'm not sure that's necessarily a bad things.

Hard to know where to draw the line.