Added PGP public key for sending security vulnerability reports.

SECURITY.md

@@ -1,5 +1,6 @@
 Security is very important to us. If you discover any issue regarding security, please disclose
-the information responsibly by sending an email to support (at) wekan.team and not by
+the information responsibly by sending an email to support (at) wekan.team using
+[this PGP public key](support-at-wekan.team_pgp-publickey.asc) and not by
 creating a GitHub issue. We will respond swiftly to fix verifiable security issues.
 
 We thank you with a place at our hall of fame page, that is

support-at-wekan.team_pgp-publickey.asc

@@ -0,0 +1,16 @@
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+Version: OpenPGP.js v4.10.8
+Comment: https://openpgpjs.org
+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+=SNk3
+-----END PGP PUBLIC KEY BLOCK-----