pl-api: detect hollo and fix sign in

Signed-off-by: nicole mikołajczyk <git@mkljczk.pl>

packages/pl-api/lib/features.ts

@@ -40,6 +40,14 @@ const FRIENDICA = 'Friendica';
  */
 const GOTOSOCIAL = 'GoToSocial';
 
+/**
+ * Hollo, federated single-user microblogging software.
+ *
+ * @category Software
+ * @see {@link https://docs.hollo.social/}
+ */
+const HOLLO = 'Hollo';
+
 /**
  * Iceshrimp, yet another Misskey fork.
  *
@@ -1820,6 +1828,7 @@ export {
   FIREFISH,
   FRIENDICA,
   GOTOSOCIAL,
+  HOLLO,
   ICESHRIMP,
   ICESHRIMP_NET,
   MASTODON,