fix(ci): pin foundry to different version (#608)

## Summary
previous version appeared to have been pulled, causing a 404??
https://github.com/foundry-rs/foundry/tags
see foundry-rs/foundry-toolchain#35

this updates it to an older version that doesn't look like it will get
pulled.

.github/workflows/test.yml

@@ -76,7 +76,7 @@ jobs:
       - name: Install Foundry
         uses: foundry-rs/foundry-toolchain@v1
         with:
-          version: "nightly-89f74f26926b552e0fbfca0858f0a129dec79881"
+          version: "nightly-60ec00296f00754bc21ed68fd05ab6b54b50e024"
       - name: Build tests
         run: |
           cargo test --no-run --release --workspace \