deps: update dependency org.postgresql:postgresql to v42.7.6 (googleapis#2074)

Author: renovate-bot

java-spanner-jdbc/samples/spring-data-jdbc/postgresql/pom.xml

@@ -72,7 +72,7 @@
     <dependency>
       <groupId>org.postgresql</groupId>
       <artifactId>postgresql</artifactId>
-      <version>42.7.5</version>
+      <version>42.7.6</version>
     </dependency>
 
     <!-- Add OpenTelemetry for tracing and metrics. -->

java-spanner-jdbc/samples/spring-data-mybatis/postgresql/pom.xml

@@ -75,7 +75,7 @@
     <dependency>
       <groupId>org.postgresql</groupId>
       <artifactId>postgresql</artifactId>
-      <version>42.7.5</version>
+      <version>42.7.6</version>
     </dependency>
     <dependency>
       <groupId>org.testcontainers</groupId>