Update 3.0.3 for release (OAI#2149)

* Update README.md for release

* Update release date for 3.0.3

Signed-off-by: Mike Ralphson <mike.ralphson@gmail.com>

versions/3.1.0.md

@@ -3435,7 +3435,7 @@ Two examples of this:
 Version   | Date       | Notes
 ---       | ---        | ---
 3.1.0     | TBD        | TBD
-3.0.3     | TBD        | Patch release of the OpenAPI Specification 3.0.3
+3.0.3     | 2020-02-20 | Patch release of the OpenAPI Specification 3.0.3
 3.0.2     | 2018-10-08 | Patch release of the OpenAPI Specification 3.0.2
 3.0.1     | 2017-12-06 | Patch release of the OpenAPI Specification 3.0.1
 3.0.0     | 2017-07-26 | Release of the OpenAPI Specification 3.0.0