build(deps): bump github.com/caddyserver/caddy from 1.0.3 to 1.0.4 (#3461)

Bumps [github.com/caddyserver/caddy](https://github.com/caddyserver/caddy) from 1.0.3 to 1.0.4.
- [Release notes](https://github.com/caddyserver/caddy/releases)
- [Commits](https://github.com/caddyserver/caddy/compare/v1.0.3...v1.0.4)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/Shopify/sarama v1.21.0 // indirect
 	github.com/apache/thrift v0.12.0 // indirect
 	github.com/aws/aws-sdk-go v1.25.36
-	github.com/caddyserver/caddy v1.0.3
+	github.com/caddyserver/caddy v1.0.4
 	github.com/coredns/federation v0.0.0-20190818181423-e032b096babe
 	github.com/coreos/go-systemd v0.0.0-20190212144455-93d5ec2c7f76 // indirect
 	github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f // indirect