Generic message types

Updated to a new version of the GIS library that supports rules with infinitely many premises. Now the development is completely parametric in the (possibly infinite) set of messages that can be exchanged over sessions.

Compatibility:

• Tested Agda 2.6.2.1 and stdlib 1.7.1
• Tested Agda 2.6.2.2 and stdlib 1.7.1

First release

Version submitted for review (ICALP 2021).