deps: bump com.google.cloud:google-cloud-spanner-jdbc (#756)

Bumps [com.google.cloud:google-cloud-spanner-jdbc](https://github.com/googleapis/java-spanner-jdbc) from 2.13.2 to 2.13.4.
- [Release notes](https://github.com/googleapis/java-spanner-jdbc/releases)
- [Changelog](https://github.com/googleapis/java-spanner-jdbc/blob/main/CHANGELOG.md)
- [Commits](googleapis/java-spanner-jdbc@v2.13.2...v2.13.4)

---
updated-dependencies:
- dependency-name: com.google.cloud:google-cloud-spanner-jdbc
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

pom.xml

@@ -13,7 +13,7 @@
     <maven.compiler.source>1.8</maven.compiler.source>
     <maven.compiler.target>1.8</maven.compiler.target>
     <hibernate.version>5.6.15.Final</hibernate.version>
-    <spanner-jdbc-driver.version>2.13.2</spanner-jdbc-driver.version>
+    <spanner-jdbc-driver.version>2.13.4</spanner-jdbc-driver.version>
     <log4j.version>2.20.0</log4j.version>
 
     <maven-surefire-plugin.version>3.1.2</maven-surefire-plugin.version>