Rename theme from Casper to Michelin and update demo URL

Author: devnied

package.json

@@ -1,7 +1,7 @@
 {
-    "name": "casper",
-    "description": "A clean, minimal default theme for the Ghost publishing platform",
-    "demo": "https://demo.ghost.io",
+    "name": "michelin",
+    "description": "Michelin default theme for Ghost publishing platform",
+    "demo": "https://blogit.michelin.io/",
     "version": "5.9.0",
     "engines": {
         "ghost": ">=5.0.0"