Switch to Hackage version of hstatistics

We were depending on Alexandre's fork of `hstatistics`, but in the
meantime his changes got merged upstream and the maintainer release
version `0.3.1` on Hackage, so this commit changes the `stack.yaml` file
to use that.
3 jobs for adinapoli/issue-180-deps-audit in 73 minutes and 49 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Test
passed #6040
deps

00:30:03

failed #6041
docs

00:12:23

passed #6042
test

00:31:22

 
Name Stage Failure
failed
docs Test
    randomString (src/Gargantext/Core/Utils.hs:59)
addTuples (src/Gargantext/Core/Utils.hs:75)
Completed 477 action(s).

-- While building package gargantext-0.0.6.9.4.3 (scroll up to its section to see the error) using:
/builds/gargantext/haskell-gargantext/.stack-root/setup-exe-cache/x86_64-linux/Cabal-simple_mPHDZzAJ_3.2.1.0_ghc-8.10.6 --builddir=.stack-work/dist/x86_64-linux/Cabal-3.2.1.0 haddock --html --hoogle --html-location=../$pkg-$version/ --haddock-option=--hyperlinked-source --haddock-option=--quickjump
Process exited with code: ExitFailure 1
Cleaning up file based variables
ERROR: Job failed: exit code 1