Allow idempotent upgrade [COOK-2843]

[Christian Höltje]

This is from COOK-2843.

Creating a recipe like:

python_pip 'diamond' do
  notifies :restart, 'service[diamond]'
  action :upgrade
end

Will always do the upgrade and trigger the notifies. Example output, using diamond:

Processing python_pip[diamond] action upgrade (docwhat-diamond::default line 29)
Upgrading python_pip[diamond] version from 4.0.435 to latest

Even though 4.0.435 is the latest version

The only workaround at the moment is to set a version number.

There was a pull request at one point for this: #38

[Noah Kantrowitz]

This cookbook and resource are deprecated. Use poise-python and python_package, they already handle this correctly.