ext/sodium: Add support for libsodium 1.0.21 APIs

Add support for new functions present in recent libsodium
versions:

- Functions for IP address encryption:
  - sodium_crypto_ipcrypt_*
  - sodium_bin2ip/sodium_ip2bin helpers

- Extendable output functions:
  - SHAKE128/SHAKE256
  - TurboSHAKE128/TurboSHAKE256

Author: jedisct1

NEWS

@@ -87,6 +87,9 @@ PHP                                                                        NEWS
   . Added AF_UNSPEC support for sock_addrinfo_lookup() as a sole umbrella for
     AF_INET* family only. (David Carlier)
 
+- Sodium:
+  . Added support for libsodium 1.0.21 IPcrypt and XOF APIs. (jedisct1)
+
 - SPL:
   . DirectoryIterator key can now work better with filesystem supporting larger
     directory indexing. (David Carlier)