Bump gradle-wrapper from 9.5.1 to 9.6.0 in /codegen in the gradle group (smithy-lang#731)

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


Updates `gradle-wrapper` from 9.5.1 to 9.6.0
- [Release notes](https://github.com/gradle/gradle/releases)
- [Commits](gradle/gradle@v9.5.1...v9.6.0)

---
updated-dependencies:
- dependency-name: gradle-wrapper
  dependency-version: 9.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: gradle
...

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Author: dependabot[bot]

codegen/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.6.0-bin.zip
 networkTimeout=10000
 retries=0
 retryBackOffMs=500