bug in purefa_certs.py

[pda79]

Error when using module purefa_certs

To Reproduce use the module with state: sign

purestorage.flasharray.purefa_certs:
    state: sign
    export_file: files/csr
    key_size: 2048

Expected behavior working csr request

Additional context Ansible Pure Collection 1.20.0

python module version: purestorage 1.19.0 py-pure-client 1.33.1

[sdodsley]

Fixed by #426