use the right nightly

Author: lalitb

.github/workflows/ci.yml

@@ -73,11 +73,11 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
         with:
-          toolchain: nightly-2024-05-01
+          toolchain: nightly-2024-06-30
           components: rustfmt
       - name: external-type-check
         run: |
-          cargo install cargo-check-external-types
+          cargo install cargo-check-external-types@0.1.13
           cd ${{ matrix.example }}
           cargo check-external-types --config allowed-external-types.toml
   non-default-examples: