add docker detect

utils.ts

@@ -270,3 +270,10 @@ export class TimeoutError extends Error {
         super("Timeout");
     }
 }
+
+let _isDocker: boolean | undefined = undefined;
+
+export function isDocker() {
+    if (_isDocker === undefined) _isDocker = parse_bool(Deno.env.get("DOCKER") ?? "false");
+    return _isDocker;
+}