deps: update camunda/identity docker tag to v8.8.0-alpha8

Author: renovate[bot]

charts/camunda-platform-8.8/values.yaml

@@ -628,7 +628,7 @@ identity:
     ## @param identity.image.repository defines which image repository to use
     repository: camunda/identity
     ## @param identity.image.tag can be set to overwrite the global tag, which should be used in that chart
-    tag: 8.8.0-alpha7
+    tag: 8.8.0-alpha8
     ## @param identity.image.digest can be used to set image digest (overrides tag if set, e.g. "sha256:abcd...")
     digest: ""
     ## @param identity.image.pullSecrets can be used to configure image pull secrets https://kubernetes.io/docs/concepts/containers/images/#specifying-imagepullsecrets-on-a-pod