maintainers: add Greg back! (envoyproxy#10284)

Hurray!

Also fix up the security team list.

Signed-off-by: Matt Klein <[email protected]>

Author: mattklein123

OWNERS.md

@@ -22,6 +22,8 @@ routing PRs, questions, etc. to the right place.
     issues, and CI in general.
 * Snow Pettersen ([snowp](https://github.com/snowp)) ([email protected])
   * Upstream, host/priority sets, load balancing, and retry plugins.
+* Greg Greenway ([ggreenway](https://github.com/ggreenway)) ([email protected])
+  * TLS, TCP proxy, listeners, and HTTP proxy/connection pooling.
 
 # Maintainers
 
@@ -40,13 +42,14 @@ routing PRs, questions, etc. to the right place.
 
 * All maintainers
 * Piotr Sikora ([PiotrSikora](https://github.com/PiotrSikora)) ([email protected])
+* Antonio Vicente ([antoniovicente](https://github.com/antoniovicente)) ([email protected])
+* Tony Allen ([tonya11en](https://github.com/tonya11en)) ([email protected])
 
 # Emeritus maintainers
 
 * Constance Caramanolis ([ccaraman](https://github.com/ccaraman)) ([email protected])
 * Roman Dzhabarov ([RomanDzhabarov](https://github.com/RomanDzhabarov)) ([email protected])
 * Bill Gallagher ([wgallagher](https://github.com/wgallagher)) ([email protected])
-* Greg Greenway ([ggreenway](https://github.com/ggreenway)) ([email protected], formerly [email protected])
 * Dan Noé ([dnoe](https://github.com/dnoe)) ([email protected])
 
 # Friends of Envoy