Bump fastutil from 8.3.1 to 8.4.0

Bumps [fastutil](https://github.com/vigna/fastutil) from 8.3.1 to 8.4.0.
- [Release notes](https://github.com/vigna/fastutil/releases)
- [Changelog](https://github.com/vigna/fastutil/blob/master/CHANGES)
- [Commits](vigna/fastutil@8.3.1...8.4.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

exist-parent/pom.xml

@@ -381,7 +381,7 @@
             <dependency>
                 <groupId>it.unimi.dsi</groupId>
                 <artifactId>fastutil</artifactId>
-                <version>8.3.1</version>
+                <version>8.4.0</version>
             </dependency>
 
             <dependency>