install dart

.github/workflows/ci.yaml

@@ -29,6 +29,12 @@ jobs:
           source $HOME/.cargo/env
           rustup toolchain install nightly
           rustup default nightly
+      - name: Dart
+        run: |
+          sudo wget -qO /etc/apt/trusted.gpg.d/dart_linux_signing_key.asc https://dl-ssl.google.com/linux/linux_signing_key.pub
+          sudo wget -qO /etc/apt/sources.list.d/dart_stable.list https://storage.googleapis.com/download.dartlang.org/linux/debian/dart_stable.list
+          sudo apt update
+          sudo apt install -y dart
       - name: Flutter
         run: |
           git clone https://github.com/flutter/flutter.git