Add netty-buffer API dependency to the cache module

The public interface of the cache module uses ByteBufs.

Signed-off-by: Graham <gpe@openrs2.dev>

cache/build.gradle.kts

@@ -4,6 +4,8 @@ plugins {
 }
 
 dependencies {
+    api("io.netty:netty-buffer:${Versions.netty}")
+
     implementation(project(":buffer"))
     implementation(project(":compress"))
     implementation(project(":crypto"))