Bump rust versions to fix CI failures

Latest rayon requires at least Rust 1.63, regex requires 1.65, and
std::hint::black_box was stabilized in 1.66, so bump that.

Also bump the current stable version to validate with a newer Rust since
presumably that's the intention of the second version.

.github/workflows/test.yml

@@ -17,8 +17,8 @@ jobs:
     strategy:
       matrix:
         rust:
-          - "1.60.0"
-          - "1.65.0"
+          - "1.66.0"
+          - "1.76.0"
     steps:
       - uses: dtolnay/rust-toolchain@master
         with: