Build failure with GHC 8.4 and up

[andreasabel]

Discovered in a routine build attempt:

Building library for credentials-0.0.2..
[1 of 5] Compiling Credentials.Types ( src/Credentials/Types.hs, /Users/abel/tmp/credentials-0.0.2/dist-newstyle/build/x86_64-osx/ghc-8.4.4/credentials-0.0.2/build/Credentials/Types.o )

src/Credentials/Types.hs:54:25: error:
    • No instance for (Semigroup Context)
        arising from the 'deriving' clause of a data type declaration
      Possible fix:
        use a standalone 'deriving instance' declaration,
          so you can specify the instance context yourself
    • When deriving the instance for (Monoid Context)
   |
54 |     deriving (Eq, Show, Monoid)
   |                         ^^^^^^
Error: cabal: Failed to build credentials-0.0.2.

Added missing upper bound base < 4.11 to hackage releases: https://hackage.haskell.org/package/credentials-0.0.2/revisions/