Align local bio limits to remote limit.

lib/pleroma/user.ex

@@ -104,7 +104,7 @@ def update_changeset(struct, params \\ %{}) do
     |> cast(params, [:bio, :name])
     |> unique_constraint(:nickname)
     |> validate_format(:nickname, ~r/^[a-zA-Z\d]+$/)
-    |> validate_length(:bio, max: 1000)
+    |> validate_length(:bio, max: 5000)
     |> validate_length(:name, min: 1, max: 100)
   end