.pullapprove.yml: Use distribution-spec-maintainers

The other groups make sense for project-template, but we only need one
set here.

Signed-off-by: W. Trevor King <[email protected]>

Author: wking

.pullapprove.yml

@@ -23,24 +23,6 @@ group_defaults:
       - master
 
 groups:
-  image-spec:
+  distribution-spec:
     teams:
-      - image-spec-maintainers
-  image-tools:
-    teams:
-      - image-tools-maintainers
-  go-digest:
-    teams:
-      - go-digest-maintainers
-  runc:
-    teams:
-      - runc-maintainers
-  runtime-spec:
-    teams:
-      - runtime-spec-maintainers
-  runtime-tools:
-    teams:
-      - runtime-tools-maintainers
-  selinux:
-    teams:
-      - selinux-maintainers
+      - distribution-spec-maintainers