chore(artifactapi): deploy v3.7.3 (#215)

## Why

artifactapi images \`v3.7.3\` are built and pushed to the registry, but au-syd1 is still running \`v3.6.5\`. This rolls the deployment forward to pick up the recent fixes.

## Changes

- \`api-deployment\`: \`artifactapi\` \`v3.6.5\` → \`v3.7.3\`
- \`ui-deployment\`: \`artifactapi-ui\` \`v3.6.5\` → \`v3.7.3\`

Included in v3.7.x since v3.6.5:
- Local-repo files now appear in the cached-objects UI (#99).
- Evicting a local RPM prunes its repodata metadata (#100).
- The bare domain redirects to the web UI at /ui (#101).

Reviewed-on: #215
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

apps/base/artifactapi/api-deployment.yaml

@@ -35,7 +35,7 @@ spec:
               mountPath: /combined-certs
       containers:
         - name: api
-          image: git.unkin.net/unkin/artifactapi:v3.6.5
+          image: git.unkin.net/unkin/artifactapi:v3.7.3
           imagePullPolicy: IfNotPresent
           ports:
             - containerPort: 8000