mention migpol in refereeing invitation mail

scipost_django/templates/email/referees/invite_contributor_to_referee.html

@@ -2,7 +2,7 @@
   Dear {% if invitation.referee %}{{ invitation.referee.profile.get_title_display }} {{ invitation.referee.user.last_name }}{% else %}{{ invitation.profile.get_title_display }} {{ invitation.profile.last_name }}{% endif %},
 </p>
 <p>
-  We have received a Submission to SciPost which, in view of your expertise and On behalf of the Editor-in-charge {{ invitation.submission.editor_in_charge.profile.get_title_display }} {{ invitation.submission.editor_in_charge.user.first_name }} {{ invitation.submission.editor_in_charge.user.last_name }}, we would like to invite you to referee:
+  We have received a Submission to {% if invitation.submission.submitted_to.doi_label == "MigPol" %}Migration Politics{% else %}SciPost{% endif %} which, in view of your expertise and On behalf of the Editor-in-charge {{ invitation.submission.editor_in_charge.profile.get_title_display }} {{ invitation.submission.editor_in_charge.user.first_name }} {{ invitation.submission.editor_in_charge.user.last_name }}, we would like to invite you to referee:
   <br />
   <br />
   {{ invitation.submission.title }}