Upgrade rust toolchain installer in github actions

actions-rs is no longer maintained and rust-bitcoin
is using dtolnay/rust-toolchain in their CI.

Author: spacebear21

.github/workflows/rust.yml

@@ -16,10 +16,7 @@ jobs:
       - name: "Checkout repo"
         uses: actions/checkout@v4
       - name: "Install ${{ matrix.rust }} toolchain"
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: ${{ matrix.rust }}
-          override: true
+        uses: dtolnay/rust-toolchain@${{ matrix.rust }}
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
       - name: Run tests
@@ -31,10 +28,7 @@ jobs:
       - name: "Checkout repo"
         uses: actions/checkout@v4
       - name: "Install nightly toolchain"
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
+        uses: actions-rs/toolchain@nightly
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
       - run: rustup component add rustfmt --toolchain nightly-x86_64-unknown-linux-gnu
@@ -47,10 +41,7 @@ jobs:
       - name: "Checkout repo"
         uses: actions/checkout@v4
       - name: "Install nightly toolchain"
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          override: true
+        uses: actions-rs/toolchain@nightly
       - name: "Use cache"
         uses: Swatinem/rust-cache@v2
       - name: "Install clippy"