Update the WDL model

updates the internal WDL model, using data from 2.6M games played by the revisions since 9fb5832.

official-stockfish#5565

No functional change

src/uci.cpp

@@ -339,8 +339,8 @@ WinRateParams win_rate_params(const Position& pos) {
     double m = std::clamp(material, 17, 78) / 58.0;
 
     // Return a = p_a(material) and b = p_b(material), see github.com/official-stockfish/WDL_model
-    constexpr double as[] = {-41.25712052, 121.47473115, -124.46958843, 411.84490997};
-    constexpr double bs[] = {84.92998051, -143.66658718, 80.09988253, 49.80869370};
+    constexpr double as[] = {-37.45051876, 121.19101539, -132.78783573, 420.70576692};
+    constexpr double bs[] = {90.26261072, -137.26549898, 71.10130540, 51.35259597};
 
     double a = (((as[0] * m + as[1]) * m + as[2]) * m) + as[3];
     double b = (((bs[0] * m + bs[1]) * m + bs[2]) * m) + bs[3];