travis.yml: install bash for fix #1

.travis.yml

@@ -16,9 +16,11 @@ script:
 - cd rootfs
 - sudo tar -zxpf ../${ROOTFS_FN}
 - sudo cp -f ../${GLIBC_FN} ./root/
+- sudo cp -f /etc/resolv.conf ./etc/resolv.conf
 - 
 - sudo chroot . /sbin/apk add /root/${GLIBC_FN} --allow-untrusted
-- sudo ln -sf ash bash
+- sudo chroot . /sbin/apk update
+- sudo chroot . /sbin/apk add bash
 - 
 - echo "# This file was automatically generated by WSL. To stop automatic generation
   of this file, remove this line." | sudo tee ./etc/resolv.conf