chore: update python version

Author: kgala2

.cl/cloudbuild.yaml

@@ -13,8 +13,8 @@
 # limitations under the License.
 
 steps:
-  - id: run integration tests 3.13
-    name: python:3.13
+  - id: run integration tests {_VERSION}
+    name: python:{_VERSION}
     entrypoint: bash
     env: 
       - "IP_TYPE=private"
@@ -23,19 +23,7 @@ steps:
       - "-c"
       - |
         pip install nox
-        nox -s system-3.13
-    waitFor: ["-"]
-  - id: run integration tests 3.9
-    name: python:3.9
-    entrypoint: bash
-    env: 
-      - "IP_TYPE=private"
-    secretEnv: ["MYSQL_CONNECTION_NAME", "MYSQL_USER", "MYSQL_IAM_USER", "MYSQL_PASS", "MYSQL_DB", "POSTGRES_CONNECTION_NAME", "POSTGRES_USER", "POSTGRES_IAM_USER", "POSTGRES_PASS", "POSTGRES_DB",  "POSTGRES_CAS_CONNECTION_NAME", "POSTGRES_CAS_PASS", "POSTGRES_CUSTOMER_CAS_CONNECTION_NAME", "POSTGRES_CUSTOMER_CAS_PASS", "POSTGRES_CUSTOMER_CAS_PASS_VALID_DOMAIN_NAME","SQLSERVER_CONNECTION_NAME", "SQLSERVER_USER", "SQLSERVER_PASS", "SQLSERVER_DB"]
-    args:
-      - "-c"
-      - |
-        pip install nox
-        nox -s system-3.9
+        nox -s system-{_VERSION}
     waitFor: ["-"]
 availableSecrets:
   secretManager:
@@ -77,6 +65,8 @@ availableSecrets:
     env: 'SQLSERVER_PASS'
   - versionName: 'projects/$PROJECT_ID/secrets/SQLSERVER_DB/versions/latest'
     env: 'SQLSERVER_DB'
+substitutions:
+  _VERSION: ${3.13,3.9}
 options:
   dynamicSubstitutions: true
   pool: