chore(ci): Use hashbrown 0.15.0 in MSRV check (#158)

* chore(ci): Use hashbrown 0.15.0 in MSRV check

* chore(ci): Use stable rust to resolve dependency

.github/workflows/CI.yml

@@ -64,15 +64,17 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Install Rust (${{ matrix.rust }})
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: ${{ matrix.rust }}
+      - uses: dtolnay/rust-toolchain@stable
       - name: Pin some dependencies for MSRV
         run: |
           cargo update
           cargo update --package tokio --precise 1.38.1
           cargo update --package tokio-util --precise 0.7.11
+          cargo update --package hashbrown --precise 0.15.0
+      - name: Install Rust (${{ matrix.rust }})
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.rust }}
       - run: cargo check --features full
 
   miri: