Enable docker api client by default (#2417)

fallback to cli with COG_DOCKER_SDK_CLIENT=0

Author: michaeldwan

pkg/docker/docker.go

@@ -2,15 +2,15 @@ package docker
 
 import (
 	"context"
-	"os"
 	"strconv"
 
 	"github.com/replicate/cog/pkg/docker/command"
+	"github.com/replicate/cog/pkg/util"
 	"github.com/replicate/cog/pkg/util/console"
 )
 
 func NewClient(ctx context.Context, opts ...Option) (command.Command, error) {
-	enabled, _ := strconv.ParseBool(os.Getenv("COG_DOCKER_SDK_CLIENT"))
+	enabled := util.GetEnvOrDefault("COG_DOCKER_SDK_CLIENT", true, strconv.ParseBool)
 	if enabled {
 		console.Debugf("Docker client: sdk")
 		return NewAPIClient(ctx, opts...)