Fix search on Oban.Pro (#11)

The adapter detection we implemented in 30e2d6c doesn't work for Oban.Pro
when one uses the `Smart` engine. Changed to a) assume Postgres for both
`Basic` and `Smart`, b) let the fallback also explicitly type cast the jsonb
column, which I believe shouldn't matter on sqlite.

lib/obanalyze/oban_jobs.ex

@@ -57,19 +57,21 @@ defmodule Obanalyze.ObanJobs do
   defp filter(query, term) do
     like = "%#{term}%"
 
-    case Oban.config() do
-      %{engine: Oban.Engines.Basic} ->
-        from oj in query,
-          where: ilike(oj.worker, ^like),
-          or_where: ilike(type(oj.args, :string), ^like)
-
-      _ ->
-        from oj in query,
-          where: like(oj.worker, ^like),
-          or_where: like(oj.args, ^like)
+    if postgres?() do
+      from oj in query,
+        where: ilike(oj.worker, ^like),
+        or_where: ilike(type(oj.args, :string), ^like)
+    else
+      from oj in query,
+        where: like(oj.worker, ^like),
+        or_where: like(type(oj.args, :string), ^like)
     end
   end
 
+  defp postgres? do
+    Oban.config().engine in [Oban.Engines.Basic, Oban.Pro.Engines.Smart]
+  end
+
   defp jobs_count_query(job_state) do
     Oban.Job
     |> where([job], job.state == ^job_state)