Add a check for config file extension before loading

[j6k4m8]

Describe your changes

This PR adds a check (per #47) that ensures the config file path ends with .yaml.

Was thinking about adding a action=... class to the argument, but feels like overkill and this is much more readable. Feedback welcome if you prefer that technique!

Issue Link

Closes #47

Type of change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📖 Documentation (Addition or improvements to documentation)

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[leifdenby]

sorry for the delay @j6k4m8 - I was off ill for a while... 😞

All the tests pass now :) Do you want to update the changelog and we can get this merged in? Remember to add yourself to the list of contributors in pyproject.toml too

[leifdenby]

It's probably fair to call this a bug I think. I would be reasonable to assume that the application supports reading both .yaml and .yml when I state that we're using "yaml" files. But with your fix only supporting .yaml is now "expected behaviour" 😄

[j6k4m8]

I'd (very gently) agree that this is a bug, but I think reasonable to just enforce .yaml for now; it's an easy enough fix and I can't imagine a circumstance where someone can't rename a yml file... But of course, happy to add support for yml if you prefer!

PS: hope you're feeling better :)

[leifdenby]

All done! Thanks for your contribution @j6k4m8 🌟