Automatically install rust toolchain for CI

It's already running on push for all branches.

.gitea/workflows/ci.yml

@@ -1,13 +1,14 @@
 name: "CI"
 on:
   push:
-  pull_request:
   workflow_dispatch:
 
 jobs:
   formatting:
     name: cargo fmt
     runs-on: ubuntu-latest
+    env:
+      RUNNER_TOOL_CACHE: /toolcache
     steps:
       - uses: actions/checkout@v6
       - uses: actions-rust-lang/setup-rust-toolchain@v1
@@ -19,6 +20,8 @@ jobs:
   test:
     name: cargo test
     runs-on: ubuntu-latest
+    env:
+      RUNNER_TOOL_CACHE: /toolcache
     steps:
       - uses: actions/checkout@v6
       - uses: actions-rust-lang/setup-rust-toolchain@v1
@@ -28,6 +31,8 @@ jobs:
   test-gpu:
     name: cargo test (GPU)
     runs-on: ubuntu-latest
+    env:
+      RUNNER_TOOL_CACHE: /toolcache
     steps:
       - uses: actions/checkout@v6
       - uses: actions-rust-lang/setup-rust-toolchain@v1

enkou-shaders-tests/build.rs

@@ -9,9 +9,11 @@ pub fn main() -> anyhow::Result<()> {
         .copied()
         .collect::<PathBuf>();
 
-    let install = Install::from_shader_crate(crate_path.clone())
-        .within_build_script()
-        .run()?;
+    let mut install = Install::from_shader_crate(crate_path.clone());
+    install.build_script = true;
+    install.auto_install_rust_toolchain = true;
+    let install = install.run()?;
+
     let mut builder = install.to_spirv_builder(crate_path, "spirv-unknown-vulkan1.3");
     builder.build_script.defaults = true;
     builder.shader_panic_strategy = ShaderPanicStrategy::SilentExit;