fix: add launcher entrypoint for CNB images on dokku run and cron:run

The scheduler-run script classified CNB-based images as `herokuish` because
`is_image_herokuish_based` returns true for them, which caused the
`docker-args-process-run` trigger for builder-pack to skip injecting
`--entrypoint launcher`. Without that flag the container fell back to the
image entrypoint (`/cnb/process/web`) and dropped the user-supplied
arguments. Mirror the deploy-side detection so CNB images set
`IMAGE_SOURCE_TYPE=pack`, allowing the launcher entrypoint to be added.

tests/apps/python/app-cnb-cron-procfile.json

@@ -0,0 +1,21 @@
+{
+  "cron": [
+    {
+      "command": "task",
+      "schedule": "5 5 5 5 5"
+    }
+  ],
+  "healthchecks": {
+    "web": [
+      {
+        "attempts": 2,
+        "content": "python/http.server",
+        "name": "check-1",
+        "path": "/",
+        "timeout": 5,
+        "type": "startup",
+        "wait": 2
+      }
+    ]
+  }
+}

tests/unit/builder-pack.bats

@@ -177,6 +177,39 @@ teardown() {
   assert_output "['task.py', 'some', 'cron', 'task']"
 }
 
+@test "(builder-pack) cron:run with Procfile reference" {
+  run /bin/bash -c "dokku config:set $TEST_APP SECRET_KEY=fjdkslafjdk"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku builder:set $TEST_APP selected pack"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run deploy_app python dokku@$DOKKU_DOMAIN:$TEST_APP cron_run_procfile_wrapper
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output_contains 'from cnb stack'
+  assert_output_contains 'Building with buildpack 1' 0
+  assert_output_contains 'Installing dependencies using pip'
+
+  cron_id="$(dokku cron:list $TEST_APP --format json | jq -r '.[0].id')"
+  run /bin/bash -c "echo $cron_id"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output_exists
+
+  run /bin/bash -c "dokku --quiet cron:run $TEST_APP $cron_id"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output "['task.py', 'test']"
+}
+
 cron_run_wrapper() {
   local APP="$1"
   local APP_REPO_DIR="$2"
@@ -187,3 +220,14 @@ cron_run_wrapper() {
   ls -lah "$APP_REPO_DIR"
   mv -f "$APP_REPO_DIR/app-cnb-cron.json" "$APP_REPO_DIR/app.json"
 }
+
+cron_run_procfile_wrapper() {
+  local APP="$1"
+  local APP_REPO_DIR="$2"
+  [[ -z "$APP" ]] && local APP="$TEST_APP"
+  APP_REPO_DIR="$(realpath "$APP_REPO_DIR")"
+
+  add_requirements_txt "$APP" "$APP_REPO_DIR"
+  ls -lah "$APP_REPO_DIR"
+  mv -f "$APP_REPO_DIR/app-cnb-cron-procfile.json" "$APP_REPO_DIR/app.json"
+}