feat(halo): update halo-pro image tag to 2.21.8

apps/apps/halo/helmchart.yaml

@@ -31,7 +31,7 @@ spec:
                     - greenhk  
     image:
       repository: halohub/halo-pro
-      tag: 2.21.7
+      tag: 2.21.8
     service:
       type: ClusterIP
     ingress: