Bump com.diffplug.spotless:spotless-plugin-gradle

Bumps the gradle group in /codegen with 1 update: [com.diffplug.spotless:spotless-plugin-gradle](https://github.com/diffplug/spotless).


Updates `com.diffplug.spotless:spotless-plugin-gradle` from 7.0.3 to 7.0.4
- [Release notes](https://github.com/diffplug/spotless/releases)
- [Changelog](https://github.com/diffplug/spotless/blob/main/CHANGES.md)
- [Commits](diffplug/spotless@gradle/7.0.3...gradle/7.0.4)

---
updated-dependencies:
- dependency-name: com.diffplug.spotless:spotless-plugin-gradle
  dependency-version: 7.0.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: gradle
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

codegen/gradle/libs.versions.toml

@@ -3,7 +3,7 @@ junit5 = "5.12.2"
 smithy = "1.58.0"
 test-logger-plugin = "4.0.0"
 spotbugs = "6.0.22"
-spotless = "7.0.3"
+spotless = "7.0.4"
 smithy-gradle-plugins = "1.2.0"
 dep-analysis = "2.17.0"
 jsoup = "1.20.1"