connect: do not restrict auto envoy version to docker task driver (#17041)

This PR updates the envoy_bootstrap_hook to no longer disable itself if
the task driver in use is not docker. In other words, make it work for
podman and other image based task drivers. The hook now only checks that

1. the task is a connect sidecar
2. the task.config block contains an "image" field

.changelog/17041.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+connect: do not restrict automatic envoy versioning to docker driver
+```

client/allocrunner/taskrunner/envoy_version_hook.go

@@ -122,8 +122,6 @@ func (_ *envoyVersionHook) interpolateImage(task *structs.Task, env *taskenv.Tas
 // its envoy proxy version resolved automatically.
 func (h *envoyVersionHook) skip(request *ifs.TaskPrestartRequest) bool {
 	switch {
-	case request.Task.Driver != "docker":
-		return true
 	case !request.Task.UsesConnectSidecar():
 		return true
 	case !h.needsVersion(request.Task.Config):
@@ -158,6 +156,10 @@ func (h *envoyVersionHook) needsVersion(config map[string]interface{}) bool {
 		return false
 	}
 
+	if _, exists := config["image"]; !exists {
+		return false
+	}
+
 	image := h.taskImage(config)
 
 	return strings.Contains(image, envoy.VersionVar)

client/allocrunner/taskrunner/envoy_version_hook_test.go

@@ -272,6 +272,7 @@ func TestTaskRunner_EnvoyVersionHook_Prestart_custom(t *testing.T) {
 	// Setup an Allocation
 	alloc := mock.ConnectAlloc()
 	alloc.Job.TaskGroups[0].Tasks[0] = mock.ConnectSidecarTask()
+	alloc.Job.TaskGroups[0].Tasks[0].Driver = "podman"
 	alloc.Job.TaskGroups[0].Tasks[0].Config["image"] = "custom-${NOMAD_envoy_version}:latest"
 	allocDir, cleanupDir := allocdir.TestAllocDir(t, logger, "EnvoyVersionHook", alloc.ID)
 	defer cleanupDir()