Release fix for GHC 8.4 and up

[andreasabel]

PR #14 fixing issue #13 was merged but not released.
The released version does not build with GHC 8.4 or up due to incompatibility with the exports of base-4.11.

• Ambiguous occurrence ‘<>’ : Database/SQL/Types.hs:481 #13

As Hackage Trustee, I revised the released versions to base < 4.11, as requested in #14 (comment) .

A release is needed.