inherit rust toolchain channel from rust-toolchain.toml

We've forked actions-rs/toolchain and merged
https://github.com/actions-rs/toolchain/pull/209
so we can take advantage of full support of `rust-toolchain.toml`.
Without that PR, the action fails because the `rustup` version
built into the runners by default is too old. #2528 covers switching
back to the upstream when it includes those changes.

.github/workflows/build.yml

@@ -16,10 +16,9 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: helix-editor/rust-toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
           override: true
 
       - uses: Swatinem/rust-cache@v1
@@ -37,10 +36,9 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: helix-editor/rust-toolchain@v1
         with:
           profile: minimal
-          toolchain: ${{ matrix.rust }}
           override: true
 
       - uses: Swatinem/rust-cache@v1
@@ -64,7 +62,6 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        rust: [stable]
 
   lints:
     name: Lints
@@ -74,10 +71,9 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: helix-editor/rust-toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
           override: true
           components: rustfmt, clippy
 
@@ -103,10 +99,9 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: helix-editor/rust-toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
           override: true
 
       - uses: Swatinem/rust-cache@v1

.github/workflows/release.yml

@@ -17,7 +17,6 @@ jobs:
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
           override: true
 
       - uses: Swatinem/rust-cache@v1