Does't works with GHC 8.0.2

[Mark-Kovalyov]

Unable to setup koans under Ubuntu 18.x , GHC 8.0.2

$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.0.2

$ uname -s -v -m -i -o
Linux #113-Ubuntu SMP Thu Jul 9 23:41:39 UTC 2020 x86_64 x86_64 GNU/Linux

$ cabal --version
cabal-install version 1.24.0.2
compiled using version 1.24.2.0 of the Cabal library 

$ ./setup-koans 
Writing a default package environment file to
/home/mayton/git.haskell/HaskellKoans/bin/cabal.sandbox.config
Using an existing sandbox located at
/home/mayton/git.haskell/HaskellKoans/bin/.cabal-sandbox
cabal: Error reading local package.
Couldn't find .cabal file in: .
setup-koans: [ERROR]cabal install --only-dependencies failed.
CallStack (from HasCallStack):
  error, called at setup-koans:10:27 in main:Main