Merge pull request #588 from arjun024/patch-2

[ARI/Buildpacks/PHP] add @arjun024 as php subteam approver

Author: Gerg

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

@@ -156,6 +156,8 @@ areas:
     github: thitch97
   - name: Sophie Wigmore
     github: sophiewigmore
+  - name: Arjun Sreedharan
+    github: arjun024
   repositories:
   - cloudfoundry/php-buildpack
   - cloudfoundry/php-buildpack-release