Bump to next alpha (#925)

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "vscode-docker",
-  "version": "0.6.2",
+  "version": "0.6.3-alpha",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vscode-docker",
-  "version": "0.6.2",
+  "version": "0.6.3-alpha",
   "preview": true,
   "publisher": "PeterJausovec",
   "displayName": "Docker",