Update cni.template

Format the cni.template, use `space` instead of some `tab`. Avoid indent issue in text editor.

Signed-off-by: bingshen.wbs <bingshen.wbs@alibaba-inc.com>

cluster/gce/cni.template

@@ -1,24 +1,26 @@
 {
   "name": "k8s-pod-network",
-    "cniVersion": "0.3.1",
-    "plugins": [
+  "cniVersion": "0.3.1",
+  "plugins": [
     {
       "type": "ptp",
       "mtu": 1460,
       "ipam": {
-	"type": "host-local",
-	"subnet": "{{.PodCIDR}}",
-	"routes": [
-	{"dst": "0.0.0.0/0"}
-	]
+        "type": "host-local",
+        "subnet": "{{.PodCIDR}}",
+        "routes": [
+          {
+            "dst": "0.0.0.0/0"
+          }
+        ]
       }
     },
     {
       "type": "portmap",
       "capabilities": {
-	"portMappings": true
+        "portMappings": true
       },
       "noSnat": true
     }
-    ]
+  ]
 }