Update ChangeLog

ChangeLog

@@ -65,6 +65,7 @@ LibreSSL Portable Release Notes:
 	* Compatibility changes
 	  - The one-step hashing functions, MD4(), MD5(), RIPEMD160(), SHA1(),
 	    all SHA-2, and HMAC() no longer support returning a static buffer.
+	    Callers must now pass in a buffer to calculate the digest.
 	  - Removed workaround for F5 middle boxes.
 	  - Removed the useless pem2.h, a public header that was added since
 	    it was too hard to add a prototype to one file.