build(deps): bump com.google.cloud:google-cloud-spanner-hibernate-tools (GoogleCloudPlatform#3216)

Bumps [com.google.cloud:google-cloud-spanner-hibernate-tools](https://github.com/GoogleCloudPlatform/google-cloud-spanner-hibernate) from 3.8.0 to 3.9.1.
- [Release notes](https://github.com/GoogleCloudPlatform/google-cloud-spanner-hibernate/releases)
- [Changelog](https://github.com/GoogleCloudPlatform/google-cloud-spanner-hibernate/blob/master/CHANGELOG.md)
- [Commits](GoogleCloudPlatform/google-cloud-spanner-hibernate@v3.8.0...v3.9.1)

---
updated-dependencies:
- dependency-name: com.google.cloud:google-cloud-spanner-hibernate-tools
  dependency-version: 3.9.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

samples/java/spring-data-jpa/pom.xml

@@ -61,7 +61,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-spanner-hibernate-tools</artifactId>
-      <version>3.8.0</version>
+      <version>3.9.1</version>
     </dependency>
     <!-- Add Hypersistence Utils for access to additional data type mappings, for example for arrays. -->
     <dependency>