fix(ci): lock nightly toolchain

.github/workflows/build.yml

@@ -15,19 +15,18 @@ env:
 
 jobs:
   build:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - name: Use nightly Rust
+        # lock to 2024-08-23 and wait for embassy-executor to be updated
         run: |
-          rustup default nightly
+          rustup default nightly-2024-08-23
           rustup component add rust-src
           rustup update
           rustup target add riscv32imac-unknown-none-elf
           rustup target add riscv32imafc-unknown-none-elf
           rustup target add riscv32i-unknown-none-elf
-          # See https://github.com/rust-lang/rust/issues/12880
-          touch ~/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/Cargo.lock
       - name: Fetch Deps
         # if this is a pull request
         if: github.event_name == 'pull_request'