Raise required compiler to rust 1.60

Required by reqwest 0.12.

    error: failed to select a version for the requirement `reqwest = "^0.12"`
    candidate versions found which didn't match: 0.11.23, 0.11.22, 0.11.21, ...
    location searched: crates.io index
    required by package `unsafe-libyaml-test-suite v0.0.0`

.github/workflows/ci.yml

@@ -37,14 +37,14 @@ jobs:
       - run: cargo test
 
   msrv:
-    name: Rust 1.56.0
+    name: Rust 1.60.0
     needs: pre_ci
     if: needs.pre_ci.outputs.continue
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.56.0
+      - uses: dtolnay/rust-toolchain@1.60.0
       - run: cargo check --lib
 
   doc:

Cargo.toml

@@ -9,7 +9,7 @@ edition = "2021"
 keywords = ["yaml"]
 license = "MIT"
 repository = "https://github.com/dtolnay/unsafe-libyaml"
-rust-version = "1.56"
+rust-version = "1.60"
 
 [workspace]
 [dev-dependencies]

README.md

@@ -17,7 +17,7 @@ of [c2rust].
 unsafe-libyaml = "0.2"
 ```
 
-*Compiler support: requires rustc 1.56+*
+*Compiler support: requires rustc 1.60+*
 
 ## License