Move myself to the list of approvers

Author: geigerj0

toc/working-groups/app-runtime-interfaces.md

@@ -60,13 +60,13 @@ areas:
     github: joergdw
   - name: Oliver Mautschke
     github: olivermautschke
+  - name: Josua Geiger
+    github: geigerj0
   reviewers:
   - name: Susanne Salzmann
     github: salzmannsusan
   - name: Sumit Kulhadia
     github: kulhadia
-  - name: Josua Geiger
-    github: geigerj0
   repositories:
   - cloudfoundry/app-autoscaler-release
   - cloudfoundry/app-autoscaler-cli-plugin