Automatic toolchain upgrade to nightly-2023-08-15 (rust-lang#2691)

Co-authored-by: celinval <[email protected]>

Author: github-actions[bot]

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2023-08-14"
+channel = "nightly-2023-08-15"
 components = ["llvm-tools-preview", "rustc-dev", "rust-src", "rustfmt"]