deps: upgrade to spanner 1.52

Author: olavloite

spanner/cloud-client/pom.xml

@@ -34,7 +34,7 @@ limitations under the License.
     <maven.compiler.source>1.8</maven.compiler.source>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <opencensus.version>0.26.0</opencensus.version>
-    <spanner.version>1.51.0</spanner.version>
+    <spanner.version>1.52.0</spanner.version>
   </properties>
 
   <!-- Include the BOM to ensure compatibility across multiple google-cloud-* libraries -->