Fix skip-host-cache deprecation warning (#1002)

skip-host-cache was deprecated in 8.0.30 and replaced by a configurable host_cache_size

https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-30.html#mysqld-8-0-30-deprecation-removal

Author: rawr51919

8.0/config/conf.d/docker.cnf

@@ -1,3 +1,3 @@
 [mysqld]
-skip-host-cache
+host_cache_size=0
 skip-name-resolve