update iceberg version

Author: razvan

docs/modules/spark-k8s/pages/usage-guide/job-dependencies.adoc

@@ -134,7 +134,7 @@ spec:
     spark.sql.catalog.local.warehouse: /tmp/warehouse
   deps:
     packages:
-      - org.apache.iceberg:iceberg-spark-runtime-3.4_2.12:1.3.1 # <1>
+      - org.apache.iceberg:iceberg-spark-runtime-3.5_2.12:1.8.1 # <1>
 ...
 ----
 

tests/templates/kuttl/iceberg/10-deploy-spark-app.yaml.j2

@@ -48,7 +48,7 @@ spec:
       #
       # We extract the spark parts from the test scenario value.
       #
-      - org.apache.iceberg:iceberg-spark-runtime-{{ ".".join(test_scenario['values']['spark'].split('.')[:2]) }}_2.12:1.5.2
+      - org.apache.iceberg:iceberg-spark-runtime-{{ ".".join(test_scenario['values']['spark'].split('.')[:2]) }}_2.12:1.8.1
   volumes:
     - name: script
       configMap: