Layer is not backwards compatible with earlier versions of Juju or Ubuntu...?

[CalvinHartwell]

Hi,

Attempting to build the charm-azure layer, but I get an error:

calvinh@calvinh-ws:~/Source/customers/h-and-m/azure-charm/charm-azure$ charm build .
build: Composing into /home/calvinh/Source/customers/h-and-m/azure-charm/charm-azure
build: Destination charm directory: /home/calvinh/Source/customers/h-and-m/azure-charm/charm-azure/builds/azure
build: Processing layer: layer:basic
build: Processing layer: layer:options
build: Processing layer: layer:status
build: Processing layer: layer:apt
build: Processing layer: azure
build: layer.yaml includes azure-integration which isn't used in metadata.yaml
Usage:   
  pip3 install [options] <requirement specifier> [package-index-options] ...
  pip3 install [options] -r <requirements file> [package-index-options] ...
  pip3 install [options] [-e] <vcs project url> ...
  pip3 install [options] [-e] <local project path> ...
  pip3 install [options] <archive url/path> ...

no such option: -d

Command failed: /tmp/tmpxglEf_/bin/pip3 install --no-binary :all: -d /tmp/tmpovQUoC -r /home/calvinh/Source/customers/h-and-m/azure-charm/charm-azure/deps/layer/layer-basic/wheelhouse.txt
calvinh@calvinh-ws:~/Source/customers/h-and-m/azure-charm/charm-azure$ 

I assume this has not been tested on Juju 2.4 or 2.3 or Ubuntu 16.04. Can you please do this?

Regards.