Updated version number to be (v3.1.4) ahead of current release (v3.1.3)

PiperOrigin-RevId: 613236845
Change-Id: I3ee759493f27cfa1e367c71e3e073b54738b73d4

unity/Editor/Bindings/MujocoBinaryRetriever.cs

@@ -37,7 +37,7 @@ public class MujocoBinaryRetriever {
           if (AssetDatabase.LoadMainAssetAtPath(mujocoPath + "/mujoco.dylib") == null) {
             File.Copy(
                 "/Applications/MuJoCo.app/Contents/Frameworks" +
-                "/mujoco.framework/Versions/Current/libmujoco.3.1.3.dylib",
+                "/mujoco.framework/Versions/Current/libmujoco.3.1.4.dylib",
                 mujocoPath + "/mujoco.dylib");
             AssetDatabase.Refresh();
           }
@@ -45,7 +45,7 @@ public class MujocoBinaryRetriever {
           if (AssetDatabase.LoadMainAssetAtPath(mujocoPath + "/libmujoco.so") == null) {
             File.Copy(
                 Environment.GetFolderPath(Environment.SpecialFolder.UserProfile) +
-                "/.mujoco/mujoco-3.1.3/lib/libmujoco.so.3.1.3",
+                "/.mujoco/mujoco-3.1.4/lib/libmujoco.so.3.1.4",
                 mujocoPath + "/libmujoco.so");
             AssetDatabase.Refresh();
           }