Add markewaite as a maintainer of the subversion plugin

Pull request to be merge:

* jenkinsci/subversion-plugin#367

Other pull requests to be considered for merging

* jenkinsci/subversion-plugin#365
* jenkinsci/subversion-plugin#363
* jenkinsci/subversion-plugin#361
* jenkinsci/subversion-plugin#351
* jenkinsci/subversion-plugin#283
* jenkinsci/subversion-plugin#282

Current maintainer that can approve the addition:

* @didiez

Author: MarkEWaite

permissions/plugin-subversion.yml

@@ -10,3 +10,4 @@ cd:
   enabled: true
 developers:
   - "didiez"
+  - "markewaite"