reflect 42.2.4 release in readme.md

[ci-skip]

README.md

@@ -23,46 +23,46 @@ Most people do not need to compile PgJDBC. You can download the precompiled driv
### Maven Central
You can search on The Central Repository with GroupId and ArtifactId [![Maven Search](https://img.shields.io/badge/org.postgresql-postgresql-yellow.svg)][mvn-search] for:

[![Java 8](https://img.shields.io/badge/Java_8-42.2.3-blue.svg)][mvn-jre8]
[![Java 8](https://img.shields.io/badge/Java_8-42.2.4-blue.svg)][mvn-jre8]
```xml
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.2.3</version>
    <version>42.2.4</version>
</dependency>
```

[![Java 7](https://img.shields.io/badge/Java_7-42.2.3.jre7-blue.svg)][mvn-jre7]
[![Java 7](https://img.shields.io/badge/Java_7-42.2.4.jre7-blue.svg)][mvn-jre7]
```xml
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.2.3.jre7</version>
    <version>42.2.4.jre7</version>
</dependency>
```

[![Java 6](https://img.shields.io/badge/Java_6-42.2.3.jre6-blue.svg)][mvn-jre6]
[![Java 6](https://img.shields.io/badge/Java_6-42.2.4.jre6-blue.svg)][mvn-jre6]
```xml
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.2.3.jre6</version>
    <version>42.2.4.jre6</version>
</dependency>
```
[mvn-search]: http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22org.postgresql%22%20AND%20a%3A%22postgresql%22 "Search on Maven Central"
[mvn-jre6]: http://search.maven.org/#artifactdetails|org.postgresql|postgresql|42.2.3.jre6|bundle
[mvn-jre7]: http://search.maven.org/#artifactdetails|org.postgresql|postgresql|42.2.3.jre7|bundle
[mvn-jre8]: http://search.maven.org/#artifactdetails|org.postgresql|postgresql|42.2.3|bundle
[mvn-jre6]: http://search.maven.org/#artifactdetails|org.postgresql|postgresql|42.2.4.jre6|bundle
[mvn-jre7]: http://search.maven.org/#artifactdetails|org.postgresql|postgresql|42.2.4.jre7|bundle
[mvn-jre8]: http://search.maven.org/#artifactdetails|org.postgresql|postgresql|42.2.4|bundle

#### Development snapshots
Snapshot builds (builds from `master` branch) are also deployed to Maven Central, so you can test current development version (test some bugfix) using:
```xml
<dependency>
  <groupId>org.postgresql</groupId>
  <artifactId>postgresql</artifactId>
  <version>42.2.4-SNAPSHOT</version> <!-- Java 8 -->
  <version>42.2.4.jre7-SNAPSHOT</version> <!-- Java 7 -->
  <version>42.2.4.jre6-SNAPSHOT</version> <!-- Java 6 -->
  <version>42.2.5-SNAPSHOT</version> <!-- Java 8 -->
  <version>42.2.5.jre7-SNAPSHOT</version> <!-- Java 7 -->
  <version>42.2.5.jre6-SNAPSHOT</version> <!-- Java 6 -->
</dependency>
```