Bump nodemailer from 6.4.6 to 6.4.16 in /web/backend/api

Bumps [nodemailer](https://github.com/nodemailer/nodemailer) from 6.4.6 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@v6.4.6...v6.4.16)

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

Author: dependabot[bot]

web/backend/api/package.json

@@ -29,7 +29,7 @@
     "mongoose": "5.9.9",
     "morgan": "1.10.0",
     "multer": "1.4.2",
-    "nodemailer": "6.4.6",
+    "nodemailer": "6.4.16",
     "utf8": "3.0.0",
     "uuid": "7.0.3"
   },

web/backend/api/yarn.lock

@@ -4816,10 +4816,10 @@ node-releases@^1.1.71:
   resolved "https://registry.yarnpkg.com/node-releases/-/node-releases-1.1.72.tgz#14802ab6b1039a79a0c7d662b610a5bbd76eacbe"
   integrity sha512-LLUo+PpH3dU6XizX3iVoubUNheF/owjXCZZ5yACDxNnPtgFuludV1ZL3ayK1kVep42Rmm0+R9/Y60NQbZ2bifw==
 
-nodemailer@6.4.6:
-  version "6.4.6"
-  resolved "https://registry.yarnpkg.com/nodemailer/-/nodemailer-6.4.6.tgz#d37f504f6560b36616f646a606894fe18819107f"
-  integrity sha512-/kJ+FYVEm2HuUlw87hjSqTss+GU35D4giOpdSfGp7DO+5h6RlJj7R94YaYHOkoxu1CSaM0d3WRBtCzwXrY6MKA==
+nodemailer@6.4.16:
+  version "6.4.16"
+  resolved "https://registry.yarnpkg.com/nodemailer/-/nodemailer-6.4.16.tgz#5cb6391b1d79ab7eff32d6f9f48366b5a7117293"
+  integrity sha512-68K0LgZ6hmZ7PVmwL78gzNdjpj5viqBdFqKrTtr9bZbJYj6BRj5W6WGkxXrEnUl3Co3CBXi3CZBUlpV/foGnOQ==
 
 nodemon@2.0.3:
   version "2.0.3"