make “powered by” translatable with i18n

packages/@uppy/dashboard/src/components/AddFiles.js

@@ -3,7 +3,7 @@ const { localIcon } = require('./icons')
 const { h, Component } = require('preact')
 
 const poweredByUppy = (props) => {
-  return <a tabindex="-1" href="https://uppy.io" rel="noreferrer noopener" target="_blank" class="uppy-Dashboard-poweredBy">Powered by <svg aria-hidden="true" class="UppyIcon uppy-Dashboard-poweredByIcon" width="11" height="11" viewBox="0 0 11 11">
+  return <a tabindex="-1" href="https://uppy.io" rel="noreferrer noopener" target="_blank" class="uppy-Dashboard-poweredBy">{props.i18n('poweredBy')} <svg aria-hidden="true" class="UppyIcon uppy-Dashboard-poweredByIcon" width="11" height="11" viewBox="0 0 11 11">
     <path d="M7.365 10.5l-.01-4.045h2.612L5.5.806l-4.467 5.65h2.604l.01 4.044h3.718z" fill-rule="evenodd" />
   </svg><span class="uppy-Dashboard-poweredByUppy">Uppy</span></a>
 }

packages/@uppy/dashboard/src/index.js

@@ -104,7 +104,8 @@ module.exports = class Dashboard extends Plugin {
           0: 'Added %{smart_count} file from %{folder}',
           1: 'Added %{smart_count} files from %{folder}',
           2: 'Added %{smart_count} files from %{folder}'
-        }
+        },
+        poweredBy: 'Powered by'
       }
     }