chore: update to Rust 1.63 (#127)

vmx · web-flow · commit 16a679b7e43c · 2023-08-01T15:06:14.000+02:00
Update to MSRV of 1.63 due to the rustix dependency.
diff --git a/Cargo.toml b/Cargo.toml
@@ -16,7 +16,7 @@ documentation = "https://docs.rs/merkletree"
 keywords = ["merkle", "merkle-tree"]
 categories = ["data-structures", "cryptography"]
 edition = "2018"
-rust-version = "1.60"
+rust-version = "1.63"
 
 [package.metadata.release]
 pre-release-commit-message = "chore(release): release {{version}}"
diff --git a/rust-toolchain b/rust-toolchain
@@ -1 +1 @@
-1.60.0
+1.63.0
