MAINTAINERS.md: Add henrywang

He'll be at least helping maintain CI and approving issues related
to that.

Author: cgwalters

MAINTAINERS.md

@@ -7,5 +7,6 @@ The current Maintainers Group for the bootc Project consists of:
 | Chris Kyrouac     | [ckyrouac](https://github.com/orgs/bootc-dev/people/ckyrouac)        | Red Hat         | Approver         |
 | Colin Walters     | [cgwalters](https://github.com/orgs/bootc-dev/people/cgwalters)      | Red Hat         | Approver         |
 | John Eckersberg   | [jeckersb](https://github.com/orgs/bootc-dev/people/jeckersb)        | Red Hat         | Approver         |
+| Xiaofeng Wang     | [henrywang](https://github.com/orgs/bootc-dev/people/henrywang)      | Red Hat         | Approver         |
 | Gursewak Mangat   | [gurusewak](https://github.com/orgs/bootc-dev/people/gursewak1997)   | Red Hat         | Approver         |
 | Joseph Corchado   | [jeckersb](https://github.com/orgs/bootc-dev/people/jmarrero)        | Red Hat         | Approver         |