Update version (#20271)

Update version to 6.6.

lerna.json

@@ -2,5 +2,5 @@
   "npmClient": "yarn",
   "npmClient": "yarn",
   "useWorkspaces": true,
   "useWorkspaces": true,
   "packages": ["packages/*"],
   "packages": ["packages/*"],
-  "version": "6.5.0-pre"
+  "version": "6.6.0-pre"
 }
 }

package.json

@@ -3,7 +3,7 @@
   "license": "Apache-2.0",
   "license": "Apache-2.0",
   "private": true,
   "private": true,
   "name": "grafana",
   "name": "grafana",
-  "version": "6.5.0-pre",
+  "version": "6.6.0-pre",
   "repository": {
   "repository": {
     "type": "git",
     "type": "git",
     "url": "http://github.com/grafana/grafana.git"
     "url": "http://github.com/grafana/grafana.git"