Nathan Williams

While reading config files, Sceptre caches the `templating_vars` between StackGroups (in `config/reader.py`). If a variable is omitted in one stack group's config, the incorrect value from another group is used....

[Resolves #937] Reset Jinja2 variable cache between config files

1

Fix for: https://github.com/Sceptre/sceptre/issues/937 This resets the Jinja2 `templating_vars` in `config/reader.py` to prevent variables leaking across StackGroups. ## PR Checklist - [x] Wrote a good commit message & description [see guide...