Terraform upgrade to 0.14.11

dockerfile: fix bad JSON syntax for volumes

Since containerd.io upgrade 1.4.6 it seems the VOLUME syntax needs to
be valid JSON.

Thanks to
https://github.com/containerd/containerd/issues/5547#issuecomment-856083714
I pinned point some existing errors when using this image.

🙇‍♂️Thanks @thaJeztah for analysing that issue!