已经选了比较低的版本了，但还是经常 遇到err
不明白怎么能制定降级版本，特别是其中的间接依赖的那些包

另外环境用 CLION+RUST
生成 cargo.lock之后 ，好想不能降级了，删除也不行？？


==========

[package]
name = "mnwlx-insight"
version = "0.1.0"
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
simple_excel_writer = "0.1.0"
#once_cell = "1.10.0"
dotenv = "0.15.0"
log = "0.4.0"
serde = { version = "1.0", features = ["derive"] }
uuid = { version = "1", features = ["v4"] }
sqlx = { version = "0.4.0", features = ["mysql", "runtime-tokio-native-tls", "macros", "chrono"] }

=======

Execution failed (exit code 101).
/Users/kevin/.cargo/bin/cargo metadata --verbose --format-version 1 --all-features
stdout :  Downloading crates ...
error: failed to download `once_cell v1.15.0`

Caused by:
  unable to get packages from source

Caused by:
  failed to parse manifest at `/Users/kevin/.cargo/registry/src/github.com-1ecc6299db9ec823/once_cell-1.15.0/Cargo.toml`

Caused by:
  feature `edition2021` is required

  this Cargo does not support nightly features, but if you
  switch to nightly channel you can add
  `cargo-features = ["edition2021"]` to enable this feature

stderr :
--
FROM 120.244.218.*