fix: changed 'utf8' to 'utf-8' for the injected script charset

Bugfix to helpers.js which specified 'utf8' rather than 'utf-8' for the script element charset.

As an aside this attribute is deprecated on script tags. It is inherited automatically as utf-8 from the document. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#Deprecated_attributes

Author: DarkPurple141

src/helpers.js

@@ -8,7 +8,7 @@ export function loadScript (url) {
     const script = document.createElement('script')
     script.async = true
     script.src = url
-    script.charset = 'utf8'
+    script.charset = 'utf-8'
 
     head.appendChild(script)
 
@@ -120,4 +120,4 @@ export const promisify = value => {
   }
 
   return Promise.resolve(value)
-}
+}