chore(docs): add new mailer option to docs

config.yml.sample

@@ -129,6 +129,8 @@ mailer:
   host: ""
   # SMTP Host port
   port: 587
+  # SMTP Auth Type. Can be either `plain`, `login` or `cram-md5`.
+  authtype: "plain"
   # SMTP username
   username: "user"
   # SMTP password

docs/content/doc/setup/config.md

@@ -665,6 +665,17 @@ Full path: `mailer.port`
 Environment path: `VIKUNJA_MAILER_PORT`
 
 
+### authtype
+
+SMTP Auth Type. Can be either `plain`, `login` or `cram-md5`.
+
+Default: `plain`
+
+Full path: `mailer.authtype`
+
+Environment path: `VIKUNJA_MAILER_AUTHTYPE`
+
+
 ### username
 
 SMTP username

pkg/mail/send_mail.go

@@ -17,10 +17,11 @@
 package mail
 
 import (
+	"io"
+
 	"code.vikunja.io/api/pkg/config"
 	"code.vikunja.io/api/pkg/log"
 	"code.vikunja.io/api/pkg/version"
-	"io"
 
 	"github.com/wneessen/go-mail"
 )