Relax superclasses for instance Arbitrary Compose

Currently we define
https://github.com/nick8325/quickcheck/blob/3c2d0d87d4b9f457a586b1cde6d1d3ac03d862bf/src/Test/QuickCheck/Arbitrary.hs#L1016-L1018

That's more restrictive than it can be, it would be nice to relax the constraint to Arbitrary (f (g a)) as in

instance Arbitrary (f (g a)) => Arbitrary (Compose f g a) where 
  arbitrary = Compose <$> arbitrary
  shrink (Compose x) = map Compose (shrink x)

This would bring the approach in line with how base defines all other instances for Compose:

instance Num (f (g a)) => Num (Compose f g a) 	
instance Read (f (g a)) => Read (Compose f g a) 	
instance Fractional (f (g a)) => Fractional (Compose f g a) 	
instance Integral (f (g a)) => Integral (Compose f g a) 	
instance Real (f (g a)) => Real (Compose f g a) 	
instance RealFrac (f (g a)) => RealFrac (Compose f g a) 	
instance Show (f (g a)) => Show (Compose f g a)

Start in src/Test/QuickCheck/Arbitrary.hs at the existing Compose Arbitrary instance around lines 1016-1018, and compare its constraint with the Compose instances in base referenced by the issue. Relax the constraint as described, then run the repository test suite and confirm that Compose values can use the broader Arbitrary instance without regressions.