Update README.md (#172)

Add CURL to list of DBs.

Signed-off-by: Oliver Chang <oliverchang@users.noreply.github.com>

README.md

@@ -12,6 +12,7 @@ This is the repository for the Open Source Vulnerability schema, which is curren
 - [AlmaLinux](https://github.com/AlmaLinux/osv-database)
 - [Haskell Security Advisories](https://github.com/haskell/security-advisories)
 - [Bitnami Vulnerability Database](https://github.com/bitnami/vulndb)
+- [Curl](https://curl.se/docs/vuln.json)
 - [OSV.dev maintained converters](https://github.com/google/osv.dev#current-data-sources)
 - [VMWare Photon OS](https://github.com/vmware/photon/wiki/Security-Advisories) (unofficial)
 - [RConsortium Advisory Database](https://github.com/RConsortium/r-advisory-database)