Bump CC:T version to 1.100

We're still a few days away from release, but don't think anything else
is going to change. And I /really/ don't want to have to write this
changelog (and then merge into later versions) on the 25th.

gradle.properties

@@ -1,5 +1,5 @@
 # Mod properties
-mod_version=1.99.1
+mod_version=1.100.0
 
 # Minecraft properties (update mods.toml when changing)
 mc_version=1.16.5