Update dependency net.neoforged:neoform-runtime to v1.0.15

Author: neoforged-renovate[bot]

src/main/java/net/neoforged/moddevgradle/dsl/NeoFormRuntime.java

@@ -13,7 +13,7 @@
  * the Minecraft artifacts for compiling and mods.
  */
 public abstract class NeoFormRuntime {
-    private static final String DEFAULT_NFRT_VERSION = "1.0.5";
+    private static final String DEFAULT_NFRT_VERSION = "1.0.15";
 
     @Inject
     public NeoFormRuntime(Project project) {