Bump nodemailer from 4.7.0 to 6.4.16

Bumps [nodemailer](https://github.com/nodemailer/nodemailer) from 4.7.0 to 6.4.16.
- [Release notes](https://github.com/nodemailer/nodemailer/releases)
- [Changelog](https://github.com/nodemailer/nodemailer/blob/master/CHANGELOG.md)
- [Commits](nodemailer/nodemailer@v4.7.0...v6.4.16)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package.json

@@ -44,7 +44,7 @@
     "morgan": "^1.9.0",
     "mustache": "^2.3.0",
     "node-restful": "^0.2.6",
-    "nodemailer": "^4.3.1",
+    "nodemailer": "^6.4.16",
     "nodemailer-html-to-text": "^3.0.0",
     "passport": "^0.3.2",
     "passport-facebook": "^2.1.1",

yarn.lock

@@ -6264,10 +6264,10 @@ nodemailer-html-to-text@^3.0.0:
   dependencies:
     html-to-text "^5.1.1"
 
-nodemailer@^4.3.1:
-  version "4.7.0"
-  resolved "https://registry.yarnpkg.com/nodemailer/-/nodemailer-4.7.0.tgz#4420e06abfffd77d0618f184ea49047db84f4ad8"
-  integrity sha512-IludxDypFpYw4xpzKdMAozBSkzKHmNBvGanUREjJItgJ2NYcK/s8+PggVhj7c2yGFQykKsnnmv1+Aqo0ZfjHmw==
+nodemailer@^6.4.16:
+  version "6.4.16"
+  resolved "https://registry.yarnpkg.com/nodemailer/-/nodemailer-6.4.16.tgz#5cb6391b1d79ab7eff32d6f9f48366b5a7117293"
+  integrity sha512-68K0LgZ6hmZ7PVmwL78gzNdjpj5viqBdFqKrTtr9bZbJYj6BRj5W6WGkxXrEnUl3Co3CBXi3CZBUlpV/foGnOQ==
 
 nopt@^4.0.1, nopt@^4.0.3:
   version "4.0.3"