Add workspace_id param to Seam constructor for use with Personal Access Token.

[DebbieAtSeam]

If you want to authenticate using a Personal Access Token (PAT), you must specify the desired workspace_id in the constructor.
Perhaps like this...

$seam = new Seam\SeamClient(
  // Specify PAT.
  $pat,
  // Specify workspace ID.
  $workspace_id,
  "https://connect.getseam.com"
);