CVE-2021-34551 and CVE-2021-3603.

Changelog excerpt:
- Increasing PHPMailer version constraints from ^6.4.1 to ^6.5 due to
  CVE-2021-34551 and CVE-2021-3603.

Author: Maikuolan

Changelog.md

@@ -21,3 +21,5 @@ __*Why "v3.0.0" instead of "v1.0.0?"*__ Because the linker is intended for use w
 ### v3.1.3
 
 [2021.05.28; Maikuolan]: Performed some minor refactoring.
+
+[2021.06.21; Security; Maikuolan]: Increasing PHPMailer version constraints from ^6.4.1 to ^6.5 due to CVE-2021-34551 and CVE-2021-3603.

composer.json

@@ -14,7 +14,7 @@
         "php": ">=7.2.0",
         "maikuolan/common": "^2.5",
         "phpmussel/core": "^3.2",
-        "phpmailer/phpmailer": "^6.4.1"
+        "phpmailer/phpmailer": "^6.5"
     },
     "suggest": {
         "phpmussel/frontend": "^3.1.1",