message: Build arbitrary feature on CI
diff: @@ -31,6 +31,7 @@ STD_FEATURES=(serde)
  check_version 1.32 && STD_FEATURES+=(rand)
  check_version 1.34 && STD_FEATURES+=(quickcheck)
  check_version 1.36 && NO_STD_FEATURES=(serde rand)
  +check_version 1.40 && STD_FEATURES+=(arbitrary)
  echo "Testing supported features: ${STD_FEATURES[*]}"
  if [ -n "${NO_STD_FEATURES[*]}" ]; then
  echo " no_std supported features: ${NO_STD_FEATURES[*]}"
  