test: bump MTK compat in downstream CI

AayushSabharwal · AayushSabharwal · commit e60a118d5e4e · 2025-03-04T12:31:04.000+05:30
diff --git a/test/downstream/Project.toml b/test/downstream/Project.toml
@@ -34,7 +34,7 @@ DelayDiffEq = "5"
 DiffEqCallbacks = "3, 4"
 ForwardDiff = "0.10"
 JumpProcesses = "9.10"
-ModelingToolkit = "9.64.1"
+ModelingToolkit = "9.64.3"
 ModelingToolkitStandardLibrary = "2.7"
 NonlinearSolve = "2, 3, 4"
 Optimization = "4"
