Currently, the documentation generation for zuul jobs fails whenever a
secret is included in any of the yaml files that are parsed by the
zuul-sphinx extension.
This is because the yaml parser is not aware of the custom tag
'!encrypted/pkcs1-oaep' and therefore fails to initialize
an appropriate python object due to a missing constructor.
This results in the following error message:
"yaml.constructor.ConstructorError: could not determine a constructor
for the tag '!encrypted/pkcs1-oaep'"
Change-Id: Id011487615a3392affd627bbdcbdbe18e58206c5
3ef1afe17e