Fix the drone.yml issue

Author: Mingshen Sun

.drone.yml

@@ -6,7 +6,7 @@ pipeline:
       - git checkout -b temp-branch-name # make a temp branch name to work around a issue in building process
       - export PYPY_USESSION_DIR=$(pwd)/pypy-usession-dir
       - mkdir pypy-usession-dir
-      - make pypy-c
+      - /bin/bash -c "make pypy-c"
   package:
     image: mesalocklinux/build-mesalock-linux
     commands: