Deploy arrstack -unkin3 (active-active code) (#388)

Deploy the merged active-active work now on each Servarr fork's main. The cluster still runs the -unkin2 images, so the merged code (K8s process lifecycle, Redis-backed distributed rate limiting, and radarr MediaCover->S3) is not yet deployed. The -unkin3 tag pipelines have built and pushed new images to docker-internal.

Changes:
- Bump sonarr app image v5.0.0-unkin2 -> v5.0.0-unkin3
- Bump radarr app image v6.4.2-unkin2 -> v6.4.2-unkin3
- Bump prowlarr app image v2.6.2-unkin2 -> v2.6.2-unkin3

Touches only the app container image line in each apps/base/arrstack/<app>/deployment.yaml; the waitfordb initContainer is unchanged.

Reviewed-on: #388
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

apps/base/arrstack/prowlarr/deployment.yaml

@@ -64,7 +64,7 @@ spec:
               memory: 64Mi
       containers:
         - name: prowlarr
-          image: artifactapi.k8s.syd1.au.unkin.net/docker-internal/prowlarr:v2.6.2-unkin2
+          image: artifactapi.k8s.syd1.au.unkin.net/docker-internal/prowlarr:v2.6.2-unkin3
           imagePullPolicy: IfNotPresent
           command:
             - /app/Prowlarr

apps/base/arrstack/radarr/deployment.yaml

@@ -64,7 +64,7 @@ spec:
               memory: 64Mi
       containers:
         - name: radarr
-          image: artifactapi.k8s.syd1.au.unkin.net/docker-internal/radarr:v6.4.2-unkin2
+          image: artifactapi.k8s.syd1.au.unkin.net/docker-internal/radarr:v6.4.2-unkin3
           imagePullPolicy: IfNotPresent
           command:
             - /app/Radarr

apps/base/arrstack/sonarr/deployment.yaml

@@ -64,7 +64,7 @@ spec:
               memory: 64Mi
       containers:
         - name: sonarr
-          image: artifactapi.k8s.syd1.au.unkin.net/docker-internal/sonarr:v5.0.0-unkin2
+          image: artifactapi.k8s.syd1.au.unkin.net/docker-internal/sonarr:v5.0.0-unkin3
           imagePullPolicy: IfNotPresent
           command:
             - /app/Sonarr