Bump dtolnay/rust-toolchain (#48)

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from 21dc36fb71dd22e3317045c0c31a3f4249868b17 to a54c7afa936fefeb4456b2dd8068152669aa8203.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](dtolnay/rust-toolchain@21dc36f...a54c7af)

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

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

Author: dependabot[bot]

.github/workflows/docker.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Setup Rust toolchain
-        uses: dtolnay/rust-toolchain@21dc36fb71dd22e3317045c0c31a3f4249868b17
+        uses: dtolnay/rust-toolchain@a54c7afa936fefeb4456b2dd8068152669aa8203
         with:
           toolchain: stable
 
@@ -61,7 +61,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Setup Rust toolchain
-        uses: dtolnay/rust-toolchain@21dc36fb71dd22e3317045c0c31a3f4249868b17
+        uses: dtolnay/rust-toolchain@a54c7afa936fefeb4456b2dd8068152669aa8203
         with:
           toolchain: stable