Enh Req: Update a Template

[jcwill23]

I'd like to be able to update a Template

Use Case:
Using the Sheet object's source attribute, a Sheet can be linked back to a Template.
If the Sheet is not flagged as an 'orphan' (that is a different functionality that prevents the update), and certain items are changed on the Sheet (for example columns added, conditional formatting updated, etc...), the Template is updated with the changes.

Alternatively, if a Sheet's source attribute could be changed to a different Template, then when a new Template is created (see issue #112), the associated Sheets would be relinked to the new version of the Template.

Use Case:
Projects are run from a set of Templates. PM's are allowed to change the structure of the sheet (columns, conditional formatting, formatting, certain formulas, etc...) and the system watches for these changes (not data changes) and puts a copy of the Sheet into a review process. When the changes are approved, the Template(s) are updated and (non-orphan) Sheets are updated with the new approved Sheets.
At the end of the process, the Templates are updated by the API.

-Craig