readthedocs: actually build the module to enable docs #125

Job	Run time
Build and test (ubuntu-22.04, 3.7)	39s
Build and test (ubuntu-22.04, 3.8)	33s
Build and test (ubuntu-22.04, 3.9)	34s
Build and test (ubuntu-22.04, 3.10)	34s
Build and test (ubuntu-22.04, 3.11)	38s
Build and test (ubuntu-22.04, 3.12)	40s
Build and test (ubuntu-22.04, pypy-3.7)	58s
Build and test (ubuntu-22.04, pypy-3.8)	55s
Build and test (ubuntu-22.04, pypy-3.9-nightly)	1m 15s
Build and test (ubuntu-22.04, pypy-3.10-nightly)	1m 12s
Build and test (macos-12, 3.7)	1m 18s
Build and test (macos-12, 3.8)	2m 17s
Build and test (macos-12, 3.9)	1m 23s
Build and test (macos-12, 3.10)	1m 14s
Build and test (macos-12, 3.11)	1m 17s
Build and test (macos-12, 3.12)	1m 21s
Build and test (macos-12, pypy-3.7)	1m 59s
Build and test (macos-12, pypy-3.8)	1m 37s
Build and test (macos-12, pypy-3.9-nightly)	2m 11s
Build and test (macos-12, pypy-3.10-nightly)	2m 7s
	24m 42s

Provide feedback