Bump dtolnay/rust-toolchain

Bumps [dtolnay/rust-toolchain](https://github.com/dtolnay/rust-toolchain) from 439cf607258077187679211f12aa6f19af4a0af7 to be73d7920c329f220ce78e0234b8f96b7ae60248.
- [Release notes](https://github.com/dtolnay/rust-toolchain/releases)
- [Commits](dtolnay/rust-toolchain@439cf60...be73d79)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/checks.yaml

@@ -68,7 +68,7 @@ jobs:
       - name: Set target rust version
         run: echo "TARGET_RUST_VERSION=$(if [ "${{matrix.rust}}" = "msrv" ]; then grep rust-version Cargo.toml | grep MSRV | cut -d'"' -f2; else echo "${{matrix.rust}}"; fi)" >> $GITHUB_ENV
       - name: Install toolchain
-        uses: dtolnay/rust-toolchain@439cf607258077187679211f12aa6f19af4a0af7
+        uses: dtolnay/rust-toolchain@be73d7920c329f220ce78e0234b8f96b7ae60248
         with:
           toolchain: "${TARGET_RUST_VERSION}"
           targets: "${{ matrix.target }}"
@@ -105,7 +105,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Install nightly toolchain
-        uses: dtolnay/rust-toolchain@439cf607258077187679211f12aa6f19af4a0af7
+        uses: dtolnay/rust-toolchain@be73d7920c329f220ce78e0234b8f96b7ae60248
         with:
           toolchain: nightly
       - name: Install udeps
@@ -161,7 +161,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Install rust toolchain
-        uses: dtolnay/rust-toolchain@439cf607258077187679211f12aa6f19af4a0af7
+        uses: dtolnay/rust-toolchain@be73d7920c329f220ce78e0234b8f96b7ae60248
         with:
           toolchain: stable
           components: rustfmt
@@ -200,7 +200,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Install rust toolchain
-        uses: dtolnay/rust-toolchain@439cf607258077187679211f12aa6f19af4a0af7
+        uses: dtolnay/rust-toolchain@be73d7920c329f220ce78e0234b8f96b7ae60248
         with:
           toolchain: stable
           components: clippy
@@ -250,7 +250,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Install nightly toolchain
-        uses: dtolnay/rust-toolchain@439cf607258077187679211f12aa6f19af4a0af7
+        uses: dtolnay/rust-toolchain@be73d7920c329f220ce78e0234b8f96b7ae60248
         with:
           toolchain: nightly
       - name: Install cargo fuzz