Fix not found link to jdbc.postgresql.org (#565)

Co-authored-by: Alexander Schwartz <[email protected]>

doc/kubernetes/modules/ROOT/partials/configure-db-connection-pool-best-practices.adoc

@@ -2,6 +2,6 @@ For the best performance, the values for the initial, minimal and maximum DB con
 This avoids creating new DB connections when a new request comes in which is costly.
 
 Keeping the DB connection open for as long as possible allows for server side statement caching that is bound to a connection.
-In the case of PostgreSQL, in order to use a server-side prepared statement, https://jdbc.postgresql.org/documentation/head/server-prepare.html[a query needs to be executed (by default) at least five times].
+In the case of PostgreSQL, in order to use a server-side prepared statement, https://jdbc.postgresql.org/documentation/server-prepare/#activation[a query needs to be executed (by default) at least five times].
 
 See the https://www.postgresql.org/docs/current/sql-prepare.html[PostgreSQL docs on prepared statements] for more information.