docs: Update the version in package.json for semantic releases.

The version is generated automatically by semantic release so we don't
need to have it here.  Having it here will just lead to confusion so
changing it.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "edx-ui-toolkit",
-  "version": "1.5.5",
+  "version": "1.0.0-semantically-released",
   "description": "A JavaScript toolkit for building edX user interfaces",
   "license": "Apache-2.0",
   "repository": {