pgjdbc: Skip test about getDefaultTransactionIsolation()

Starting with version 42.7.0, the driver issues a query statement like

  SELECT *
  FROM pg_catalog.pg_settings
  WHERE name=default_transaction_isolation

This is not supported by CrateDB.

Author: amotl

by-language/java-qa/src/test/java/io/crate/qa/JdbcMetaDataTest.java

@@ -191,6 +191,8 @@ public void test_getDatabaseProductVersion() throws Exception {
     }
 
     @Test
+    @Ignore("Not supported by CrateDB after pgjdbc 42.7.0 changed the implementation")
+    // https://github.com/crate/crate/issues/15113
     public void test_getDefaultTransactionIsolation() throws Exception {
         try (var conn = DriverManager.getConnection(URL)) {
             assertThat(conn.getMetaData().getDefaultTransactionIsolation(), is(Connection.TRANSACTION_READ_COMMITTED));