[COMMIT scylla-cluster-tests master] fix(gce_provision): move to latest scylla==4.6.3

[Commit Bot]

From: Israel Fruchter <fr...@scylladb.com>
Committer: Israel Fruchter <israel....@gmail.com>
Branch: master

fix(gce_provision): move to latest scylla==4.6.3

Since there a new java security fix, that breaks nodetool in
older scylla versions, we should be move to lastest release.

```
nodetool: Failed to connect to '127.0.0.1:7199' - URISyntaxException:
'Malformed IPv6 address at index 7: rmi://[127.0.0.1]:7199'.
```

---
diff --git a/test-cases/PR-provision-test.yaml b/test-cases/PR-provision-test.yaml
--- a/test-cases/PR-provision-test.yaml
+++ b/test-cases/PR-provision-test.yaml
@@ -22,7 +22,7 @@ instance_provision: 'spot'

gce_image_db: 'https://www.googleapis.com/compute/v1/projects/centos-cloud/global/images/family/centos-7'

-scylla_version: 4.4.1
+scylla_version: 4.6.3

workaround_kernel_bug_for_iotune: true