Bump dtolnay/rust-toolchain (#183)

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from 3c5f7ea28cd621ae0bf5283f0e981fb97b8a7af9 to 67ef31d5b988238dd797d409d6f9574278e20537.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](dtolnay/rust-toolchain@3c5f7ea...67ef31d)

---
updated-dependencies:
- dependency-name: dtolnay/rust-toolchain
  dependency-version: 67ef31d5b988238dd797d409d6f9574278e20537
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/builds.yml

@@ -125,7 +125,7 @@ jobs:
 
       # ---------- Rust toolchain ----------
       - name: Install Rust (stable)
-        uses: dtolnay/rust-toolchain@3c5f7ea28cd621ae0bf5283f0e981fb97b8a7af9
+        uses: dtolnay/rust-toolchain@67ef31d5b988238dd797d409d6f9574278e20537
         with:
           toolchain: stable
 

.github/workflows/cpp-checks.yml

@@ -85,7 +85,7 @@ jobs:
           run-clang-tidy --help | head -1 || true
 
       - name: Install Rust (stable)
-        uses: dtolnay/rust-toolchain@3c5f7ea28cd621ae0bf5283f0e981fb97b8a7af9
+        uses: dtolnay/rust-toolchain@67ef31d5b988238dd797d409d6f9574278e20537
         with:
           toolchain: stable
 

.github/workflows/make-release.yml

@@ -127,7 +127,7 @@ jobs:
 
       # ---------- Rust toolchain ----------
       - name: Install Rust (stable)
-        uses: dtolnay/rust-toolchain@3c5f7ea28cd621ae0bf5283f0e981fb97b8a7af9
+        uses: dtolnay/rust-toolchain@67ef31d5b988238dd797d409d6f9574278e20537
         with:
           toolchain: stable
 

.github/workflows/tests.yml

@@ -127,7 +127,7 @@ jobs:
 
       # ---------- Rust toolchain ----------
       - name: Install Rust (stable)
-        uses: dtolnay/rust-toolchain@3c5f7ea28cd621ae0bf5283f0e981fb97b8a7af9
+        uses: dtolnay/rust-toolchain@67ef31d5b988238dd797d409d6f9574278e20537
         with:
           toolchain: stable
 
@@ -334,7 +334,7 @@ jobs:
 
       # ---------- Rust toolchain ----------
       - name: Install Rust (stable)
-        uses: dtolnay/rust-toolchain@3c5f7ea28cd621ae0bf5283f0e981fb97b8a7af9
+        uses: dtolnay/rust-toolchain@67ef31d5b988238dd797d409d6f9574278e20537
         with:
           toolchain: stable