Improvement to Training

@pcheong-lbg suggests we add details to our section oh choosing dependencies to cover:

> Add something around exit strategy, software currency and support - which are things we need to consider when deciding on an OSS dependency

Locate the training section on choosing dependencies and read its surrounding guidance first. Add details covering exit strategy, software currency, and support when evaluating an open-source dependency; done means those considerations are clearly included in that section.

Written by the indexing model from the issue text.