Use allowlisted Rust toolchain action revision

AI Disclosure: This code was written in part by an AI agent.:

Author: timsaucer

.github/workflows/build.yml

@@ -48,7 +48,7 @@ jobs:
       - uses: actions/checkout@v6
 
       - name: Setup Rust
-        uses: dtolnay/rust-toolchain@4be7066ada62dd38de10e7b70166bc74ed198c30
+        uses: dtolnay/rust-toolchain@4cda84d5c5c54efe2404f9d843567869ab1699d4
         with:
           toolchain: "nightly"
           components: rustfmt
@@ -152,7 +152,7 @@ jobs:
           path: .
 
       - name: Setup Rust
-        uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8
+        uses: dtolnay/rust-toolchain@4cda84d5c5c54efe2404f9d843567869ab1699d4
 
       - name: Cache Cargo
         uses: Swatinem/rust-cache@v2
@@ -231,7 +231,7 @@ jobs:
           path: .
 
       - name: Setup Rust
-        uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8
+        uses: dtolnay/rust-toolchain@4cda84d5c5c54efe2404f9d843567869ab1699d4
 
       - name: Cache Cargo
         uses: Swatinem/rust-cache@v2
@@ -286,7 +286,8 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8
+      - name: Setup Rust
+        uses: dtolnay/rust-toolchain@4cda84d5c5c54efe2404f9d843567869ab1699d4
 
       - run: rm LICENSE.txt
       - name: Download LICENSE.txt
@@ -368,7 +369,8 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8
+      - name: Setup Rust
+        uses: dtolnay/rust-toolchain@4cda84d5c5c54efe2404f9d843567869ab1699d4
 
       - run: rm LICENSE.txt
       - name: Download LICENSE.txt