gsk: Lower version requirement

Author: bilelmoussaoui

gsk4/sys/Cargo.toml

@@ -49,7 +49,7 @@ version = "4.10"
 version = "4.14"
 
 [package.metadata.system-deps.gtk4.v4_16]
-version = "4.16"
+version = "4.15"
 
 [package.metadata.docs.rs]
 rustc-args = ["--cfg", "docsrs"]