Support `containers` version `0.8`.

[jonathanknowles]

Version 0.8 of the containers package has been released, but nothunks currently has an upper bound of < 0.8:

nothunks/nothunks.cabal

Lines 43 to 44 in 11bb093

	build-depends: base >= 4.12 && < 5
	, containers >= 0.5 && < 0.8

I was able to build and test successfully with the following command:

cabal test all \
    --constraint=containers==0.8 \
    --allow-newer=nothunks:containers \
    --allow-newer=ghc-heap:containers \
    --allow-newer=hashable:containers \
    --allow-newer=hedgehog:containers \
    --allow-newer=wl-pprint-annotated:containers

Related upstream issues:

• ⚫ Support containers version 0.8 in ghc-heap
• Support containers version 0.8. haskell-unordered-containers/hashable#319
• Support containers version 0.8. hedgehogqa/haskell-hedgehog#542
• Support containers version 0.8. minad/wl-pprint-annotated#12

[ivanperez-keera]

@coot would you accept such a PR?

[coot]

Yes, that's a welcomed contribution.