Merge branch 'renovate/github.com-jhillyerd-enmime-0.x' into 'master'

Update module jhillyerd/enmime to v0.8.4

See merge request !7

go.mod

@@ -4,7 +4,7 @@ go 1.15
 
 require (
 	github.com/chrj/smtpd v0.2.0
-	github.com/jhillyerd/enmime v0.8.3
+	github.com/jhillyerd/enmime v0.8.4
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/oschwald/geoip2-golang v1.4.0
 	github.com/prometheus/client_golang v1.9.0