add rust-toolchain.toml (#281)

.github/workflows/main.yml

@@ -97,10 +97,8 @@ jobs:
         with:
           distribution: 'oracle'
           java-version: '17'
-      - name: Setup Rust
-        run: |
-          rustup update
-          rustup default 1.85.1
+      - name: Check rust-toolchain.toml
+        run: rustup show
       - run: flutter pub get
       - run: flutter build apk --release
       - uses: actions/upload-artifact@v4

rust-toolchain.toml

@@ -0,0 +1,3 @@
+[toolchain]
+channel = "1.85.1"
+targets = ["aarch64-linux-android", "armv7-linux-androideabi", "x86_64-linux-android"]