Allow template-haskell-2.20 to unblock GHC 9.6
As a Hackage trustee I made a matching revision: https://hackage.haskell.org/package/string-interpolate-0.3.2.0/revisions/
As a Hackage trustee I made a matching revision: https://hackage.haskell.org/package/string-interpolate-0.3.2.0/revisions/