Bump MSRV to 1.63 due to rustix sub-dependency MSRV

Author: hoxxep

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        rust: ["1.60", stable, beta, nightly]
+        rust: ["1.63", stable, beta, nightly]
         os: [ubuntu-latest, macos-latest, windows-latest]
     steps:
     - uses: actions/checkout@master

Cargo.toml

@@ -10,7 +10,7 @@ description = """
 An implementation of the GNU make jobserver for Rust
 """
 edition = "2021"
-rust-version = "1.60"
+rust-version = "1.63"
 
 [target.'cfg(unix)'.dependencies]
 libc = "0.2.50"