chore: only depend on tomli for older pythons #1249

Job	Run time
Check coding standards	24s
Run tests (Ubuntu, 3.8)	1m 46s
Run tests (Ubuntu, 3.9)	1m 52s
Run tests (Ubuntu, 3.10)	2m 0s
Run tests (Ubuntu, 3.11)	1m 50s
Run tests (Ubuntu, 3.12)	2m 4s
Run tests (MacOS, 3.8)	2m 32s
Run tests (MacOS, 3.9)	1m 30s
Run tests (MacOS, 3.10)	2m 14s
Run tests (MacOS, 3.11)	2m 8s
Run tests (MacOS, 3.12)	1m 39s
Run tests (Windows, 3.9)	3m 26s
Run tests (Windows, 3.10)	3m 50s
Run tests (Windows, 3.11)	3m 40s
Run tests (Windows, 3.12)	3m 11s
Build distribution	0s
Upload release to PyPI	0s
Sign the Python 🐍 distribution 📦 with Sigstore and upload them to GitHub Release	0s
Upload homebrew formula	0s
	34m 6s

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