#575: Add proper permission for pixiebrix.com

[fregante]

• Fixes Minor issue: Devtools pane thinks it doesn't have access to app.pixiebrix.com #575

I verified that this change does not disable the extension using an unlisted extension:

1. Installed extension that looked like:

   {
      "permissions": [ "storage" ]
   }

2. Added a content script for https://*.pixiebrix.com/* (which is what we already have)

   {
   +   "content_scripts": [ {
   +      "css": [ "style.css" ],
   +      "matches": [ "https://*.pixiebrix.com/*" ],
   +      "run_at": "document_idle"
   +  } ],
      "permissions": [ "storage" ]
   }

3. The extension was disabled as expected: ✅

3. Then I added https://*.pixiebrix.com/* to the permissions array

   {
      "content_scripts": [ {
         "css": [ "style.css" ],
         "matches": [ "https://*.pixiebrix.com/*" ],
         "run_at": "document_idle"
      } ],
   -    "permissions": [ "storage" ]
   +    "permissions": [ "https://*.pixiebrix.com/*", "storage" ]
   }

4. The extension was not disabled 🎉

[fregante]

If you want to personally verify the changes (and also for future reference), here are the full versions I uploaded to the store:

• Step 2: awesome_extension-21.10.1.zip
• Step 3: awesome_extension-21.10.2.zip

[twschiller]

Thanks for checking that it doesn't disable the extension!