message: docs: adding dropbox to  cncf-envoy-distributors-announce
diff: @@ -423,3 +423,4 @@ and security team to ensure they still qualify for inclusion on the list.
  | envoy-security@tetrate.io | Tetrate | No | 12/19 |
  | security@vmware.com | VMware | No | 12/19 |
  | envoy-security@pinterest.com | Pinterest | Yes | 12/19 |
  +| envoy-security@dropbox.com | Dropbox | Yes | 01 /20 |
  