Revert change to JS package

This matches the version number in the Python package, and allows
bumpversion to continue working. We can revisit changing this version
later, but currently this version will never be updated again, as
bumpversion will not match this string anymore.

Fixes #1326

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "sphinx_rtd_theme",
-  "version": "1.1.0-alpha.0",
+  "version": "1.0.1alpha1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

package.json

@@ -1,7 +1,7 @@
 {
   "name": "sphinx_rtd_theme",
   "main": "js/theme.js",
-  "version": "1.1.0-alpha.0",
+  "version": "1.0.1alpha1",
   "scripts": {
     "dev": "webpack-dev-server --open --config webpack.dev.js",
     "build": "webpack --config webpack.prod.js",