Update deprecated internal link to FLE driver spec
@@ -63,7 +63,7 @@ Seek help in the slack channel \#drivers-fle.
After you have a binding, integrate libmongocrypt in your driver to
support client side encryption.
-See the [driver spec](https://docs.google.com/document/d/1yg4m_ptf5YtZdmNDNMcpcpsvrtnLF1xOPLx8D5BpAJw)
+See the [driver spec](https://github.com/mongodb/specifications/blob/master/source/client-side-encryption/client-side-encryption.rst)
for a reference of the user-facing API. libmongocrypt is needed for:
- Automatic encryption/decryption
