Running tox locally or through zuul would fail with
puppet-lint warnings.
This was introduced by puppet-lint 2.4.0 and still exists
in 2.4.1
2.3.6 works as expected, so now we are clamping
to that version.
Change-Id: I19a1d4df2b299e4dcb581df43874d8e1866b3962
Closes-Bug: 1847534
Signed-off-by: Al Bailey <Al.Bailey@windriver.com>