resolver.rubykaigi.net: remove dupe CAA definition

Author: sorah

route53/rubykaigi.net.route

@@ -85,16 +85,6 @@ template 'rubykaigi.net-common' do
 end
 
 template 'rubykaigi.net-public' do
-  rrset 'resolver.rubykaigi.net', 'CAA' do
-    ttl 300
-    resource_records(
-      *[
-        'letsencrypt.org',
-        'amazonaws.com',
-        'sectigo.com',  # ZeroSSL
-       ].map {|cn| "0 issue \"#{cn}\"" }
-    )
-  end
 end
 
 template 'rubykaigi.net-private' do