Make cabal-cache non-fatal

.github/scripts/cabal-cache.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+case "$(uname -s)" in
+	MSYS_*|MINGW*)
+		ext=".exe"
+		;;
+	*)
+		ext=""
+	   ;;
+esac
+
+if [ "${CABAL_CACHE_DISABLE}" = "yes" ] ; then
+	echo "cabal-cache disabled (CABAL_CACHE_DISABLE set)"
+elif [ "${CABAL_CACHE_NONFATAL}" = "yes" ] ; then
+	time "cabal-cache${ext}" "$@" || echo "cabal-cache failed (CABAL_CACHE_NONFATAL set)"
+else
+	time "cabal-cache${ext}" "$@"
+	exit $?
+fi
+