gradle: 8.6 -> 8.7

pkgs/development/tools/build-managers/gradle/default.nix

···
   # https://docs.gradle.org/current/userguide/compatibility.html
 
   gradle_8 = gen {
-    version = "8.6";
+    version = "8.7";
     nativeVersion = "0.22-milestone-25";
-    hash = "sha256-ljHVPPPnS/pyaJOu4fiZT+5OBgxAEzWUbbohVvRA8kw=";
+    hash = "sha256-VEw11r2Emuil7QvOo5umd9xA9J330YNVYVgtogCblh0=";
     defaultJava = jdk21;
   };