Correct licence identifier #46

Job	Run time
build (macos-latest, 4.06.x)	17m 40s
build (macos-latest, 4.14.x)	11m 19s
build (macos-latest, 5.1.x)	13m 18s
build (macos-latest, ocaml-variants.5.2.0+trunk)	11m 59s
build (ubuntu-latest, 4.06.x)	3m 43s
build (ubuntu-latest, 4.14.x)	1m 42s
build (ubuntu-latest, 5.1.x)	1m 33s
build (ubuntu-latest, ocaml-variants.5.2.0+trunk)	1m 41s
build (windows-latest, 4.06.x)	2m 42s
build (windows-latest, 4.14.x)	3m 35s
	1h 9m 12s

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