Fix regression with partitioned tables in PostgreSQL

Add handling for detecting existence of partitioned tables explicitly.

PostgreSQL JDBC Driver update from 42.2.10 to 42.2.25 in #113 caused
partitioned tables to broke due upstream change of separating types of
normal table and partitioned table as explained in
pgjdbc/pgjdbc#1708

src/main/java/io/aiven/connect/jdbc/dialect/GenericDatabaseDialect.java

@@ -501,7 +501,7 @@ public boolean tableExists(
             tableId.catalogName(),
             tableId.schemaName(),
             tableId.tableName(),
-            new String[]{"TABLE"}
+            new String[]{"TABLE", "PARTITIONED TABLE"}
         )) {
             final boolean exists = rs.next();
             log.info("Using {} dialect table {} {}", this, tableId, exists ? "present" : "absent");