Update README.md badge to Lucene 9.4.2 (#1392)

README.md

@@ -3,7 +3,7 @@
 [![PyPI](https://img.shields.io/pypi/v/pyserini?color=brightgreen)](https://pypi.org/project/pyserini/)
 [![PyPI Download Stats](https://img.shields.io/pypi/dw/pyserini?color=brightgreen)](https://pypistats.org/packages/pyserini)
 [![Maven Central](https://img.shields.io/maven-central/v/io.anserini/anserini?color=brightgreen)](https://search.maven.org/search?q=a:anserini)
-[![Generic badge](https://img.shields.io/badge/Lucene-v9.3.0-brightgreen.svg)](https://archive.apache.org/dist/lucene/java/9.3.0/)
+[![Generic badge](https://img.shields.io/badge/Lucene-v9.4.2-brightgreen.svg)](https://archive.apache.org/dist/lucene/java/9.4.2/)
 [![LICENSE](https://img.shields.io/badge/license-Apache-blue.svg?style=flat)](https://www.apache.org/licenses/LICENSE-2.0)
 
 Pyserini is a Python toolkit for reproducible information retrieval research with sparse and dense representations.