Add generic-lens to testedPackages

scripts/build-all.nix

@@ -64,7 +64,8 @@ let
 
   # The packages which we are here to test
   testedPackages = with nixpkgs.haskell.lib; with haskellPackages; {
-    inherit lens aeson criterion scotty;
+    inherit lens aeson criterion scotty generic-lens;
+
     # servant: Don't distribute Sphinx documentation
     servant = overrideCabal servant { postInstall = ""; };
     # singletons: Disable testsuite since it often breaks due to spurious