Upgrade curl to 7.64.1

Test: build
Change-Id: I31c820b646e6b7ef71e5f8763071f18d8933cb28
diff --git a/docs/CIPHERS.md b/docs/CIPHERS.md
index 0d3be3b..c011804 100644
--- a/docs/CIPHERS.md
+++ b/docs/CIPHERS.md
@@ -496,3 +496,4 @@
 `CALG_ECDH`,
 `CALG_ECMQV`,
 `CALG_ECDSA`,
+`CALG_ECDH_EPHEM`,