Bump to 1.15 because build numbers have reset

Signed-off-by: shedaniel <daniel@shedaniel.me>

gradle.properties

@@ -6,7 +6,7 @@ supported_version=1.16.4/5
 
 archives_base_name=architectury
 archives_base_name_snapshot=architectury-snapshot
-base_version=1.14
+base_version=1.15
 maven_group=me.shedaniel
 
 fabric_loader_version=0.11.1