[docs] Update fluss-versions.json for 0.8.0 RC1

Author: wuchong

website/fluss-versions.json

@@ -1,26 +1,37 @@
 [
   {
     "versionName": "next",
-    "fullVersion": "0.8-SNAPSHOT",
-    "shortVersion": "0.8-SNAPSHOT",
-    "dockerVersion": "0.8-SNAPSHOT"
+    "fullVersion": "0.9-SNAPSHOT",
+    "shortVersion": "0.9",
+    "dockerVersion": "0.9-SNAPSHOT",
+    "released": false
+  },
+  {
+    "versionName": "version-0.8",
+    "fullVersion": "0.8.0-incubating",
+    "shortVersion": "0.8",
+    "dockerVersion": "0.8.0-incubating-rc1",
+    "released": false
   },
   {
     "versionName": "version-0.7",
     "fullVersion": "0.7.0",
     "shortVersion": "0.7",
-    "dockerVersion": "0.7.0"
+    "dockerVersion": "0.7.0",
+    "released": true
   },
   {
     "versionName": "version-0.6",
     "fullVersion": "0.6.1",
     "shortVersion": "0.6",
-    "dockerVersion": "0.6.1"
+    "dockerVersion": "0.6.1",
+    "released": true
   },
   {
     "versionName": "version-0.5",
     "fullVersion": "0.5.0",
     "shortVersion": "0.5",
-    "dockerVersion": "0.5.0"
+    "dockerVersion": "0.5.0",
+    "released": true
   }
 ]