Add cors headers to HKP views

app/hkp/views.py

@@ -23,4 +23,7 @@ def lookup(request):
     if not request.user.has_perm("pgp.view_publickey", key):
         raise Http404()
 
-    return HttpResponse(key.armor, content_type="application/pgp-keys")
+    response = HttpResponse(key.armor, content_type="application/pgp-keys")
+    response["Access-Control-Allow-Origin"] = "*"
+    response["Access-Control-Allow-Methods"] = "GET, OPTIONS, HEAD"
+    return response