Can't add stack description with latest version of troposphere

If I have a stacker definition that includes a description, like
```
stacks:
- name: myStack
class_path: ...
stack_name: ...
description: My lovely stack
region: ...
```

I get the following error when trying to build the stack

```
AttributeError: `Template` object has no attribute `add_description`
```

I believe this has to do with some changes made on the 3.0.0 troposphere release

https://github.com/cloudtools/troposphere/blob/7bf20c3b58730f93bfaecd5f2171c3157f53fa05/CHANGELOG.rst#300-20210705

Stacker seems to be calling add_description but it has been updated to set_description.

Stacker 1.7.2
troposphere 3.0.3
Python 3.9.7
Windows 10