Lint: Fix: [306] Shells that use pipes should set the pipefail option

[tangrufus]

Tested deploy without subdirectory and rollback.

Need help testing deploy with subdirectory and Lets Encrypt.

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Discussion: Is it safe to assume bash lives at /bin/bash?

Alternatively, we can do executable: {{ bash_path }}
See also:

trellis/roles/letsencrypt/tasks/certificates.yml

Line 30 in f11a7ce

executable: /bin/bash

[swalkinshaw]

safe to assume bash lives at /bin/bash

Should be since we only support Ubuntu