update OCaml 5.1 to the latest hash of 5.1.1 #3784

Job	Run time
nix-fmt-check	1m 17s
Native (Top-level) packages (ubuntu-latest)	39s
Native (Top-level) packages (macos-13)	1m 48s
Native packages (macOS, OCaml 4_14)	24m 50s
Native packages (Linux, OCaml 4_14)	9m 24s
Native packages (macOS, OCaml 5_0)	27m 40s
arm64 packages (OCaml 4_14)	10m 58s
Native packages (Linux, OCaml 5_0)	11m 46s
Native packages (macOS, OCaml 5_1)	3h 7m 26s
musl packages (OCaml 4_14)	44s
arm64 packages (OCaml 5_0)	12m 15s
Native packages (Linux, OCaml 5_1)	1h 37m 3s
musl packages (OCaml 5_0)	45s
arm64 packages (OCaml 5_1)	20m 46s
musl packages (OCaml 5_1)	10m 50s
	6h 58m 11s

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