Shorten badge cache age on README.md

Reduced from 30 days to 1 day.

Author: drewnoakes

README.md

@@ -1,7 +1,7 @@
 ![metadata-extractor logo](https://cdn.rawgit.com/drewnoakes/metadata-extractor/master/Resources/metadata-extractor-logo.svg)
 
 [![metadata-extractor build status](https://github.com/drewnoakes/metadata-extractor/actions/workflows/maven.yml/badge.svg)](https://github.com/drewnoakes/metadata-extractor/actions/workflows/maven.yml)
-[![Maven Central](https://img.shields.io/maven-central/v/com.drewnoakes/metadata-extractor.svg?maxAge=2592000)](https://mvnrepository.com/artifact/com.drewnoakes/metadata-extractor)
+[![Maven Central](https://img.shields.io/maven-central/v/com.drewnoakes/metadata-extractor.svg?maxAge=86400)](https://mvnrepository.com/artifact/com.drewnoakes/metadata-extractor)
 [![Donate](https://img.shields.io/badge/paypal-donate-yellow.svg)](https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=TNXDJKCDV5Z2C&lc=GB&item_name=Drew%20Noakes&item_number=metadata%2dextractor&no_note=0&cn=Add%20a%20message%20%28optional%29%3a&no_shipping=1&currency_code=GBP&bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted)
 
 _metadata-extractor_ is a Java library for reading metadata from media files.