chore: re-enable mdformat-gfm #67

Job	Run time
Test documentation build	44s
Test Python package build (macos-12)	33s
Lint & Test (macos-12)	3m 5s
Test Python package build (windows-2022)	48s
Lint & Test (windows-2022)	3m 15s
CodeQL (javascript)	46s
Test Python package build (ubuntu-22.04)	21s
Lint & Test (ubuntu-22.04)	1m 34s
Test Briefcase build (macos-12)	3m 24s
CodeQL (python)	2m 1s
Test Briefcase build (windows-2022)	6m 13s
Test Briefcase build (ubuntu-22.04)	3m 22s
Upload coverage	2s
Deploy github pages	47s
Briefcase build & draft release	0s
Publish to PyPi	0s
	26m 55s

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