Update spanner client version. (#36995)

* Update spanner client version.

* Edit comments with a new issue id.

Author: shunping

buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy

@@ -612,8 +612,8 @@ class BeamModulePlugin implements Plugin<Project> {
     def google_ads_version = "33.0.0"
     def google_clients_version = "2.0.0"
     def google_cloud_bigdataoss_version = "2.2.26"
-    // [bomupgrader] TODO(#35868): currently pinned, should be determined by: com.google.cloud:google-cloud-spanner, consistent with: google_cloud_platform_libraries_bom
-    def google_cloud_spanner_version = "6.95.1"
+    // [bomupgrader] TODO(#37008): currently pinned before gcp-bom moving beyond this version, should be determined by: com.google.cloud:google-cloud-spanner, consistent with: google_cloud_platform_libraries_bom
+    def google_cloud_spanner_version = "6.104.0"
     def google_code_gson_version = "2.10.1"
     def google_oauth_clients_version = "1.34.1"
     // [bomupgrader] determined by: io.grpc:grpc-netty, consistent with: google_cloud_platform_libraries_bom