Add Valkey 9.0 valkey.conf (#376)

Signed-off-by: Jacob Murphy <[email protected]>

Author: murphyjacob4

topics/valkey.conf.md

@@ -34,6 +34,7 @@ The list of configuration directives, and their meaning and intended usage
 is available in the self documented example valkey.conf shipped into the
 Valkey distribution.
 
+* The self documented [valkey.conf for Valkey 9.0](https://raw.githubusercontent.com/valkey-io/valkey/9.0/valkey.conf).
 * The self documented [valkey.conf for Valkey 8.1](https://raw.githubusercontent.com/valkey-io/valkey/8.1/valkey.conf).
 * The self documented [valkey.conf for Valkey 8.0](https://raw.githubusercontent.com/valkey-io/valkey/8.0/valkey.conf).
 * The self documented [valkey.conf for Valkey 7.2](https://raw.githubusercontent.com/valkey-io/valkey/7.2/valkey.conf).