无法指定 `edition2021` 以在 Rust 中使用不稳定的包

我想通过Cargo运行一个示例，但我遇到了一个错误:

error: failed to parse manifest at `/Users/aviralsrivastava/dev/subxt/Cargo.toml`

完整的堆栈跟踪是:

error: failed to parse manifest at `/Users/aviralsrivastava/dev/subxt/Cargo.toml`

Caused by:
  feature `edition2021` is required

  The package requires the Cargo feature called `edition2021`, but that feature is not stabilized in this version of Cargo (1.56.0-nightly (b51439fd8 2021-08-09)).
  Consider adding `cargo-features = ["edition2021"]` to the top of Cargo.toml (above the [package] table) to tell Cargo you are opting in to use this unstable feature.
  See https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#edition-2021 for more information about the status of this feature.

根据建议，我继续修改Cargo .汤姆:

  Consider adding `cargo-features = ["edition2021"]` to the top of Cargo.toml (above the [package] table) to tell Cargo you are opting in to use this unstable feature.
diff --git a/Cargo.toml b/Cargo.toml
index 26a02c7..186d09b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [workspace]
 members = [".", "cli", "codegen", "macro"]
-
+cargo-features = ["edition2021"]
 [package]
 name = "subxt"
 version = "0.15.0"
(END)

我仍然面临着相同的错误，就好像toml文件中没有任何更改一样.

如何解决上述错误以使用不稳定的软件包？