Restrict benchmarks to GHC >= 8.0

Author: Bodigrim

benchmarks/text-benchmarks.cabal

@@ -15,7 +15,7 @@ category:            Text
 build-type:          Simple
 tested-with:    GHC==9.0.1,
                 GHC==8.10.4, GHC==8.8.4, GHC==8.6.5, GHC==8.4.4,
-                GHC==8.2.2, GHC==8.0.2, GHC==7.10.3
+                GHC==8.2.2, GHC==8.0.2
 
 extra-source-files:
     include/*.h