Adding a validationExceptions.json to pass Package Validation Suite's CoreModule failures on 2020.1 and 2019.1

Author: modrimkus-unity

validationExceptions.json

@@ -0,0 +1,9 @@
+{
+    "Exceptions":
+    [
+        {
+             "ValidationTest": "API Validation",
+             "PackageVersion": "5.0.3"
+       }
+    ]
+}