Bump stylelint from 15.6.0 to 16.14.1 #111

Job	Run time
Build (github-pages gem)	41s
Build (jekyll gem) (3.9, ubuntu-latest, 2.7)	1m 7s
Test CSS and JS (18.x)	3s
Build (jekyll gem) (3.9, ubuntu-latest, 3.1)	22s
Build (jekyll gem) (3.9, macos-latest, 2.7)	1m 19s
Build (jekyll gem) (3.9, macos-latest, 3.1)	35s
Build (jekyll gem) (3.9, windows-latest, 2.7)	2m 53s
Build (jekyll gem) (3.9, windows-latest, 3.1)	2m 22s
Build (jekyll gem) (4.3, ubuntu-latest, 2.7)	1m 21s
Build (jekyll gem) (4.3, ubuntu-latest, 3.1)	32s
Build (jekyll gem) (4.3, macos-latest, 2.7)	1m 48s
Build (jekyll gem) (4.3, macos-latest, 3.1)	32s
Build (jekyll gem) (4.3, windows-latest, 2.7)	4m 28s
Build (jekyll gem) (4.3, windows-latest, 3.1)	2m 23s
	20m 26s

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