Merge branch 'master' into ci/weak_mem and bump gpfsl

opam

theories/lang/adequacy.v

theories/lang/heap.v

theories/lang/lang.v

theories/lang/lib/arc.v

theories/lang/lifting.v

theories/lang/memcpy.v

theories/lang/proofmode.v

theories/lang/swap.v

theories/lifetime/at_borrow.v

theories/lifetime/frac_borrow.v

theories/lifetime/lifetime.v

theories/lifetime/lifetime_sig.v

theories/lifetime/model/accessors.v

theories/lifetime/model/borrow.v

theories/lifetime/model/borrow_sep.v

theories/lifetime/model/creation.v

theories/lifetime/model/definitions.v

theories/lifetime/model/faking.v

theories/lifetime/model/primitive.v