affinity for serving deployments was incorrectly put under containers…

[stephanbertl]

…. It needs to be put at pod spec level.

What this PR does / why we need it:

Checklist

• [x] Reviewed the CONTRIBUTING.md guide (required)
• [x] Verify the work you plan to merge addresses an existing issue (If not, open a new one) (required)
• [x] Check your branch with helm lint (required)
• [x] Update version in Chart.yaml according semver rules (required)
• [x] Substitute annotations section in Chart.yaml annotating implementations (useful for Artifecthub changelog) (required)
• [x] Update chart README using helm-docs (required)

Which issue(s) this PR fixes:

affinity for serving deployments was incorrectly put under containers. It needs to be put at pod spec level.

Special notes for your reviewer:

[stephanbertl]

@valeriano-manassero would you kindly check the helm-docs issue for me again? I am unable to do this from a linux machine currently.