Restrict approvals for community static content

The intent here is to make really sure that we only accept changes that
match upstream exactly.

content/en/community/static/OWNERS

@@ -0,0 +1,7 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+# Disable inheritance to encourage careful review of any changes here.
+options:
+  no_parent_owners: true
+approvers:
+- sig-docs-leads