Revert "Don't pass --pids-limit for now"

This reverts commit 5e54b63.

Author: alexcrichton

src/docker.rs

@@ -21,6 +21,7 @@ impl Container {
                                    .arg("--cap-drop=ALL")
                                    .arg("--memory=128m")
                                    .arg("--net=none")
+                                   .arg("--pids-limit=5")
                                    .arg("--security-opt=no-new-privileges")
                                    .arg("--interactive")
                                    .arg(name)