Add validation for crate/package name in new/init #3820

Job	Run time
Generate Matrix	4s
Check ${{ matrix.platform.target }}	0s
Test Alpine Linux	0s
Test Auditwheel	0s
Test Cross Compile	0s
Test Docker	0s
Test Bootstrap (ubuntu-latest)	3m 2s
Test Bootstrap (macos-14)	3m 9s
Test Bootstrap (windows-latest)	7m 13s
Test Emscripten	0s
Test downstream - ${{ matrix.downstream.repository }}	0s
Test MSRV	1m 28s
Test Pyston	0s
Test (ubuntu-latest, 3.12)	25m 42s
Test (ubuntu-latest, pypy3.10)	8m 34s
Test (macos-14, 3.12)	7m 6s
Test (windows-latest, 3.12)	17m 37s
Test (windows-latest, pypy3.10)	20m 3s
conclusion	1s
	1h 33m 59s

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