Update README.rst

Added TS-228A

Author: cr4nk89

README.rst

@@ -67,6 +67,8 @@ This library has been tested against the following devices and firmwares:
 +--------------+-----------------------+---------------------------------------+
 | TS-251B      | 4.4.3                 |                                       |
 +--------------+-----------------------+---------------------------------------+
+| TS-228A      | 5.0.1                 | This device does not report CPU temps |
++--------------+-----------------------+---------------------------------------+
 | TS-251+      | 4.5.1                 | No information on dnsInfo             |
 +--------------+-----------------------+---------------------------------------+
 | TS-253 Pro   | 4.5.2                 |                                       |