Align node 'engines' tag with our pre-requisite documentation

Fixes eclipse-theia#2887

- align our `engines` tag in `package.json` found at the root
of the repository with the prerequisites. This will fail to compile
the code if there is an unsupported node version being used.

Signed-off-by: Vincent Fugnitto <[email protected]>

package.json

@@ -4,7 +4,7 @@
   "version": "0.0.0",
   "engines": {
     "yarn": "1.0.x || >=1.2.1",
-    "node": ">=10.2.0"
+    "node": ">=10.2.0 <12"
   },
   "resolution": {
     "**/@types/node": "~10.3.6"