Upgrade to Argo Rollouts v1.8.3

[jgwest]

Update to latest release of Argo Rollouts: https://github.com/argoproj/argo-rollouts/releases/tag/v1.8.3
Before merging this PR, ensure you check the Argo Rollouts change logs and release notes:

• Ensure there are no changes to the Argo Rollouts install YAML that we need to respond to with changes in the operator
  • You can do this by downloading the 'install.yaml' from both the previous version (for example, v1.7.1) and new version (for example, v1.7.2), and then comparing them using a tool like Meld or diff.
  • If there are changes to resources like Deployments and Roles in the install.yaml between the two versions, this will likely require a corresponding code change within the operator. e.g. a new permission added to a Role would require a change to the Role creation code in the operator.
• Ensure there are no backwards incompatible API/behaviour changes in the change logs

[jgwest]

I've verified that there are no install changes (e.g. in Rollouts' install.yaml) that we need to respond to.

[Rizwana777]

LGTM

[jgwest]

Thanks @Rizwana777!