fix(opensearch): Fix insecure file permissions

[siegfriedweber]

Description

Fix insecure file permissions in the OpenSearch image

Part of stackabletech/opensearch-operator#46

Definition of Done Checklist

Note

Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant.

Please make sure all these things are done and tick the boxes

• Changes are OpenShift compatible
• Add an entry to the CHANGELOG.md file
• Integration tests ran successfully

TIP: Running integration tests with a new product image

The image can be built and uploaded to the kind cluster with the following commands:

boil build <IMAGE> --image-version <RELEASE_VERSION> --strip-architecture --load
kind load docker-image <MANIFEST_URI> --name=<name-of-your-test-cluster>

See the output of boil to retrieve the image manifest URI for <MANIFEST_URI>.

[labrenbe]

lgtm