chore(deps): update dependency com.google.cloud:google-cloud-spanner to v6.84.0 (googleapis#3491)

Author: renovate-bot

benchmarks/pom.xml

@@ -92,7 +92,7 @@
  <dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-spanner</artifactId>
- <version>6.81.1</version>
+ <version>6.84.0</version>
  </dependency>
  <dependency>
  <groupId>commons-cli</groupId>

samples/install-without-bom/pom.xml

@@ -33,7 +33,7 @@
  <dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-spanner</artifactId>
- <version>6.81.1</version>
+ <version>6.84.0</version>
  </dependency>
  <!-- [END spanner_install_without_bom] -->