♻️ Update integrant to latest version

This upgrade also includes complete elimination of use spec
from the backend codebase, completing the long running migration
to fully use malli for validation and decoding.

backend/src/app/migrations.clj

@@ -11,7 +11,6 @@
    [app.db :as db]
    [app.migrations.clj.migration-0023 :as mg0023]
    [app.util.migrations :as mg]
-   [clojure.spec.alpha :as s]
    [integrant.core :as ig]))
 
 (def migrations
@@ -435,9 +434,9 @@
     (mg/setup! conn)
     (mg/migrate! conn {:name name :steps migrations})))
 
-(defmethod ig/pre-init-spec ::migrations
-  [_]
-  (s/keys :req [::db/pool]))
+(defmethod ig/assert-key ::migrations
+  [_ {:keys [::db/pool]}]
+  (assert (db/pool? pool) "expected valid pool"))
 
 (defmethod ig/init-key ::migrations
   [module {:keys [::db/pool]}]