Change test date value

Using value 01/01/0001 could be represented as 1/1/0001 in a machine using a different regional format, and thus cause the test to fail

Author: irvinesunday

test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=False.verified.txt

@@ -22,6 +22,6 @@
         ]
       }
     ],
-    "aDate": "01/01/0001"
+    "aDate": "12/12/2022"
   }
 }

test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=True.verified.txt

@@ -1 +1 @@
-{"value":{"versions":[{"status":"Status1","id":"v1","links":[{"href":"http://example.com/1","rel":"sampleRel1"}]},{"status":"Status2","id":"v2","links":[{"href":"http://example.com/2","rel":"sampleRel2"}]}],"aDate":"01/01/0001"}}
+{"value":{"versions":[{"status":"Status1","id":"v1","links":[{"href":"http://example.com/1","rel":"sampleRel1"}]},{"status":"Status2","id":"v2","links":[{"href":"http://example.com/2","rel":"sampleRel2"}]}],"aDate":"12/12/2022"}}

test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.cs

@@ -97,7 +97,7 @@ public class OpenApiExampleTests
                         }
                     }
                 },
-                ["aDate"] = new OpenApiDate(DateTime.MinValue)
+                ["aDate"] = new OpenApiDate(DateTime.Parse("12/12/2022 00:00:00"))
             }
         };