CI and Dockerfile: use rust-toolchain.toml (#45)

Rely entirely on `rust-toolchain.toml` as the source of truth regarding
Rust toolchain version, profile, components, etc.

.github/workflows/rust.yml

@@ -27,14 +27,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Set up cargo/rust
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          components: rustfmt, clippy
-
-      # https://github.com/Swatinem/rust-cache
-      - name: Cache Rust stuff
-        uses: Swatinem/rust-cache@v1
+        uses: actions-rust-lang/setup-rust-toolchain@v1
 
       - name: Install latest nextest release
         uses: taiki-e/install-action@nextest

Dockerfile

@@ -1,10 +1,10 @@
 # Build the `zkbtc` binary
-FROM rust:1.76 as build
+FROM rust as build
 
 WORKDIR /app
 
 COPY ./src ./src
-COPY Cargo.* .
+COPY Cargo.* rust-toolchain.toml ./
 
 RUN cargo build --release
 

rust-toolchain.toml

@@ -0,0 +1,4 @@
+[toolchain]
+channel = "1.76.0"
+components = [ "rustfmt", "clippy" ]
+profile = "minimal"