Automatic toolchain upgrade to nightly-2023-06-23 (rust-lang#2591)

Update Rust toolchain from nightly-2023-06-22 to nightly-2023-06-23 without any other source changes.

Author: github-actions[bot]

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2023-06-22"
+channel = "nightly-2023-06-23"
 components = ["llvm-tools-preview", "rustc-dev", "rust-src", "rustfmt"]