mail/phpmailer6: Update to 6.4.0

Changelog:

- Revert change that made the mail() and sendmail transports set the envelope sender if one isn't explicitly provided, as it causes problems described in https://github.com/PHPMailer/PHPMailer/issues/2298
- Check for mbstring extension before decoding addresss in parseAddress
- Add Serbian Latin translation (sr_latn)
- Enrol PHPMailer in Tidelift

Sponsored by: Netzkommune GmbH

mail/phpmailer6/Makefile

 PORTNAME=	phpmailer
-PORTVERSION=	6.3.0
+PORTVERSION=	6.4.0
 DISTVERSIONPREFIX=	v
 CATEGORIES=	mail
 PKGNAMESUFFIX=	6

mail/phpmailer6/distinfo

-TIMESTAMP = 1615406876
-SHA256 (PHPMailer-PHPMailer-v6.3.0_GH0.tar.gz) = c6d4d2a91f33dad5303d652c32047f5d0a0914037a68fdf57db4291a3711d100
-SIZE (PHPMailer-PHPMailer-v6.3.0_GH0.tar.gz) = 97016
+TIMESTAMP = 1618688641
+SHA256 (PHPMailer-PHPMailer-v6.4.0_GH0.tar.gz) = 4315ca6227f777a8f991e618a2c4cf46f513ec5248f17c242502085e72024863
+SIZE (PHPMailer-PHPMailer-v6.4.0_GH0.tar.gz) = 97758

mail/phpmailer6/pkg-plist

@@ -46,6 +46,7 @@
 %%DATADIR%%/language/phpmailer.lang-sk.php
 %%DATADIR%%/language/phpmailer.lang-sl.php
 %%DATADIR%%/language/phpmailer.lang-sr.php
+%%DATADIR%%/language/phpmailer.lang-sr_latn.php
 %%DATADIR%%/language/phpmailer.lang-sv.php
 %%DATADIR%%/language/phpmailer.lang-tl.php
 %%DATADIR%%/language/phpmailer.lang-tr.php