Use nightly rust-toolchain in CI

Author: workingjubilee

.github/workflows/run-ci-script.yml

@@ -52,7 +52,7 @@ jobs:
         with:
           # FIXME: change to nightly once https://github.com/rust-lang/packed_simd/pull/350 is merged
           # needs to be kept in sync with the toolchain files
-          toolchain: nightly-2023-06-14
+          toolchain: nightly
           targets: ${{ inputs.target }}
           components: rustfmt
       - name: Generate Lockfile