assert_can_execute breaking api change with addition of env parameter

[bdoyle0182]

With the addition of the env parameter, any plugin that called assert_can_execute prior to this will be broken. I'm attempting to use the pybuilder-docker plugin and am facing this issue. Can we give env a default of None env=None so that it remains backwards compatible for plugins that were potentially already using it?

I created a pr for them to fix the issue, but I don't know if the plugin is being maintained or not.

for reference: AlienVault-Engineering/pybuilder-docker#7

[arcivanov]

Thanks for the report. I'll see if it's possible to default to a specific environment as a reasonable default, but even then the system might not work.

[bdoyle0182]

Thanks, yea I know it changed with a minor version so it's understandable that you're not responsible for dealing with it but it would be nice to have that default if possible