message: Add gpg key for security mail
diff: @@ -7,7 +7,13 @@ This project is still under development, the primary goal at this stage is to im
  ## Reporting a vulnerability
  -All security bugs should be reported by sending email to [Nervos Security Team](mailto:security@nervos.org). This will deliver a message to Nervos Security Team who handle security issues. Your report will be acknowledged within 24 hours, and you'll receive a more detailed response to your email within 72 hours indicating the next steps in handling your report.
  +All security bugs should be reported by sending email to [Nervos Security Team <security@nervos.org>](mailto:security@nervos.org). Please encrypt your mail using GPG using following public key.
  +
  +* Unique ID: `Nervos Security Team <security@nervos.org>`
  +* Fingerprint: C3D9 CF8A 1450 D04B 997E 4E31 6CBD D93A 0C9F 6BCD
  +* Import from keys.openpgp.org: [0C9F6BCD](https://keys.openpgp.org/search?q=security@nervos.org)
  +
  +This will deliver a message to Nervos Security Team who handle security issues. Your report will be acknowledged within 24 hours, and you'll receive a more detailed response to your email within 72 hours indicating the next steps in handling your report.
  After the initial reply to your report the security team will endeavor to keep you informed of the progress being made towards a fix and full announcement.
  