More downgrades for CI crates

Author: cuviper

ci/test_full.sh

@@ -83,9 +83,16 @@ case "${STD_FEATURES[*]}" in
  cd ci/big_serde
  cargo test
  ) ;;&
- *rand*) cargo test --manifest-path ci/big_rand/Cargo.toml ;;&
+ *rand*) (
+ cd ci/big_rand
+ check_version 1.63.0 || cargo update -p libc --precise 0.2.163
+ check_version 1.61.0 || cargo update -p ppv-lite86 --precise 0.2.17
+ cargo test
+ ) ;;&
  *quickcheck*) (
  cd ci/big_quickcheck
+ check_version 1.63.0 || cargo update -p libc --precise 0.2.163
+ check_version 1.61.0 || cargo update -p syn --precise 2.0.67
  cargo test
  ) ;;&
 esac