Bump com.diffplug.spotless from 6.9.0 to 6.9.1 (#2725)

Bumps com.diffplug.spotless from 6.9.0 to 6.9.1.

---
updated-dependencies:
- dependency-name: com.diffplug.spotless
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle

@@ -20,7 +20,7 @@ buildscript {
 }
 
 plugins {
-    id 'com.diffplug.spotless' version '6.9.0'
+    id 'com.diffplug.spotless' version '6.9.1'
     id 'eclipse'
     id 'com.github.ben-manes.versions' version '0.42.0'
     id 'biz.aQute.bnd.builder' version '6.3.1'