Don't use underscore in subdomain

Even though it's perfectly valid, some providers (Paddle in our case) don't validate URLs with an underscore in them as valid, an easy fix is just using a dash instead.

app/Commands/ShareCurrentWorkingDirectoryCommand.php

@@ -13,7 +13,7 @@ class ShareCurrentWorkingDirectoryCommand extends ShareCommand
         $this->input->setArgument('host', $host);
 
         if (! $this->option('subdomain')) {
-            $subdomain = str_replace('.', '_', basename(getcwd()));
+            $subdomain = str_replace('.', '-', basename(getcwd()));
             $this->input->setOption('subdomain', $subdomain);
         }