Revert "Correct uses of project_name in pyproject.toml"

[dstansby]

Reverts #309. It turns out this was incorrect... source: a new package I just made. maybe at some point we should add some regression tests for the contents of pyproject.toml?

[samcunliffe]

The old module/package/slug confusion? Yeah, it's a bit disturbing that we didn't have a test that failed for #309.

add some regression tests for the contents of pyproject.toml?

Are you thinking just a simple diff with an expected output? We could try to test some edge cases, at least (different project name w.r.t. slug with spaces).

[paddyroddy]

Reverts #309. It turns out this was incorrect... source: a new package I just made. maybe at some point we should add some regression tests for the contents of pyproject.toml?

I was surprised when you said this wasn't working! But blindly trusted, so yes we need a test.

[dstansby]

Are you thinking just a simple diff with an expected output?

Yes, but I think worth merging this first to un-break the templating, and I can open a new issue for better tests.

[dstansby]

Issue opened at #329