ci: change rust-toolchain format to toml (aws#5070)

Author: CarolYeh910

.github/workflows/ci_rust.yml

@@ -306,9 +306,15 @@ jobs:
 
       - uses: camshaft/rust-cache@v1
 
+      - uses: SebRollen/[email protected]
+        id: read_toml
+        with:
+          file: '${{env.ROOT_PATH}}/rust-toolchain.toml'
+          field: 'toolchain.channel'
+
       # Enforce that clippy's msrv matches rust-toolchain
       - name: Check MSRV
-        run: grep $(cat ${{env.ROOT_PATH}}/rust-toolchain) ${{env.ROOT_PATH}}/.clippy.toml
+        run: grep "${{steps.read_toml.outputs.value}}" ${{env.ROOT_PATH}}/.clippy.toml
 
       # We don't need to format the generated files,
       # but if they don't exist other code breaks.
@@ -327,15 +333,22 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: true
+
+      - uses: SebRollen/[email protected]
+        id: read_toml
+        with:
+          file: '${{env.ROOT_PATH}}/rust-toolchain.toml'
+          field: 'toolchain.channel'
+
       # Enforce crate msrv matches rust-toolchain
       - name: Check MSRV of s2n-tls
-        run: grep "rust-version = \"$(cat ${{env.ROOT_PATH}}/rust-toolchain)\"" ${{env.ROOT_PATH}}/s2n-tls/Cargo.toml
+        run: grep "rust-version = \"${{steps.read_toml.outputs.value}}\"" ${{env.ROOT_PATH}}/s2n-tls/Cargo.toml
 
       - name: Check MSRV of s2n-tls-sys
-        run: grep "rust-version = \"$(cat ${{env.ROOT_PATH}}/rust-toolchain)\"" ${{env.ROOT_PATH}}/s2n-tls-sys/templates/Cargo.template
+        run: grep "rust-version = \"${{steps.read_toml.outputs.value}}\"" ${{env.ROOT_PATH}}/s2n-tls-sys/templates/Cargo.template
 
       - name: Check MSRV of s2n-tokio
-        run: grep "rust-version = \"$(cat ${{env.ROOT_PATH}}/rust-toolchain)\"" ${{env.ROOT_PATH}}/s2n-tls-tokio/Cargo.toml
+        run: grep "rust-version = \"${{steps.read_toml.outputs.value}}\"" ${{env.ROOT_PATH}}/s2n-tls-tokio/Cargo.toml
 
   pcaps:
     runs-on: ubuntu-24.04

bindings/rust/extended/rust-toolchain

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "1.63.0"

bindings/rust/extended/rust-toolchain.toml

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "stable"

bindings/rust/standard/bench/rust-toolchain

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "1.74.0"