deps: bump commons-io:commons-io from 2.20.0 to 2.21.0 (#606)

Bumps [commons-io:commons-io](https://github.com/apache/commons-io) from 2.20.0 to 2.21.0.
- [Changelog](https://github.com/apache/commons-io/blob/master/RELEASE-NOTES.txt)
- [Commits](https://github.com/apache/commons-io/compare/rel/commons-io-2.20.0...rel/commons-io-2.21.0)

---
updated-dependencies:
- dependency-name: commons-io:commons-io
  dependency-version: 2.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

bukkit/build.gradle

@@ -24,7 +24,7 @@ dependencies {
     compileOnly 'com.github.retrooper:packetevents-spigot:2.9.4'
     compileOnly 'com.github.dmulloy2:ProtocolLib:5.3.0'
     compileOnly 'org.projectlombok:lombok:1.18.38'
-    compileOnly 'commons-io:commons-io:2.20.0'
+    compileOnly 'commons-io:commons-io:2.21.0'
     compileOnly 'org.json:json:20250517'
     compileOnly 'net.william278:minedown:1.8.2'
     compileOnly 'de.exlll:configlib-yaml:4.6.3'