Upgrade PostgreSql Docker image to version 14.3

Closes #1267

Author: schauder

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/testing/PostgresDataSourceConfiguration.java

@@ -44,7 +44,7 @@ protected DataSource createDataSource() {
 
 		if (POSTGRESQL_CONTAINER == null) {
 
-			PostgreSQLContainer<?> container = new PostgreSQLContainer<>();
+			PostgreSQLContainer<?> container = new PostgreSQLContainer<>("postgres:14.3");
 			container.start();
 
 			POSTGRESQL_CONTAINER = container;

spring-data-r2dbc/src/test/java/org/springframework/data/r2dbc/testing/PostgresTestSupport.java

@@ -118,7 +118,7 @@ private static ExternalDatabase testContainer() {
 
 			try {
 				PostgreSQLContainer container = new PostgreSQLContainer(
-						PostgreSQLContainer.IMAGE + ":" + PostgreSQLContainer.DEFAULT_TAG);
+						"postgres:14.3");
 				container.start();
 
 				testContainerDatabase = ProvidedDatabase.builder(container).database(container.getDatabaseName()).build();