try @testing-repo 3

applications/podman.sls

@@ -1,3 +1,6 @@
+include:
+  - system.apk
+
 applications_podman_pkgs:
   pkg.installed:
     - pkgs:
@@ -8,7 +11,7 @@ application_podman_compose_pkg:
   pkg.installed:
     - pkgs:
       - podman-compose
-    - fromrepo: https://dl-cdn.alpinelinux.org/alpine/edge/testing
+    - fromrepo: testing
     - require:
       - applications_podman_pkgs
 

system/apk.sls

@@ -0,0 +1,5 @@
+system_apk_testing-repo:
+  pkgrepo.managed:
+    - name: https://dl-cdn.alpinelinux.org/alpine/edge/testing
+    - dist: testing
+    - file: /etc/apk/repositories