Update default net to nn-517c4f68b5df.nnue

SPSA: https://tests.stockfishchess.org/tests/view/611cf0da4977aa1525c9ca03
Parameters: 256 net weights and 8 net biases (output layer)
Base net: nn-ac5605a608d6.nnue
New net: nn-517c4f68b5df.nnue

STC:
LLR: 2.93 (-2.94,2.94) <-0.50,2.50>
Total: 11600 W: 998 L: 851 D: 9751
Ptnml(0-2): 30, 705, 4186, 846, 33
https://tests.stockfishchess.org/tests/view/611f84524977aa1525c9cb5b

LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 9360 W: 338 L: 243 D: 8779
Ptnml(0-2): 0, 220, 4151, 303, 6
https://tests.stockfishchess.org/tests/view/611f8c5b4977aa1525c9cb64

closes https://github.com/official-stockfish/Stockfish/pull/3667

Bench: 4844618

src/evaluate.h

@@ -39,7 +39,7 @@ namespace Eval {
   // The default net name MUST follow the format nn-[SHA256 first 12 digits].nnue
   // for the build process (profile-build and fishtest) to work. Do not change the
   // name of the macro, as it is used in the Makefile.
-  #define EvalFileDefaultName   "nn-ac5605a608d6.nnue"
+  #define EvalFileDefaultName   "nn-517c4f68b5df.nnue"
 
   namespace NNUE {