V2.7.0: Minor updates

Version 2.7.0 is a library update and feature update. See below for library-specific change information.

All:
Updated Gradle to 7.0.4
Updated target SDK to v31
Updated gms:play-services-maps to 18.0.2

Aeris Core:
ADD - conditions - support for new conditions endpoint
MOD - fires - support for new fire perimeter information
MOD - alerts - support for dataSource
MOD - advisories - deprecated, use alerts instead
FIX - Various minor bug fixes and improvements

Demo App:
MOD - update for v2.7.0 libraries
MOD - update the Detailed Weather to use the conditions endpoint vs. observations
MOD - update the Weather Overview to use the conditions endpoint vs. observations
FIX - Various minor bug fixes and improvements