set version to v0.1.5

Author: andrewwinters5000

Project.toml

@@ -1,7 +1,7 @@
 name = "TrixiBottomTopography"
 uuid = "86af9953-43df-404b-8eaa-d20d82623a82"
 authors = ["maxbertrand1996 <maxbertrand1996@googlemail.com>", "Andrew R. Winters <andrew.ross.winters@liu.se>"]
-version = "0.1.5-DEV"
+version = "0.1.5"
 
 [deps]
 Downloads = "f43a241f-c20a-4ad4-852c-f6b1247861c6"