chore(deps): update dependency google-cloud-spanner to v3.12.1

fixes #746

Author: vi3k6i5

setup.py

@@ -17,7 +17,7 @@
 # 'Development Status :: 4 - Beta'
 # 'Development Status :: 5 - Production/Stable'
 release_status = "Development Status :: 5 - Production/Stable"
-dependencies = ["sqlparse >= 0.3.0", "google-cloud-spanner == 3.11.1"]
+dependencies = ["sqlparse >= 0.3.0", "google-cloud-spanner >= 3.12.1"]
 extras = {
     "tracing": [
         "opentelemetry-api >= 1.1.0",