updating ci yml

.gitlab-ci.yml

-image: cirrusci/flutter:stable
+image: dart:stable
 
 stages:
   - build
   - deploy
 
+variables:
+  FLUTTER_VERSION: stable
+
+before_script:
+  - apt-get update && apt-get install -y curl unzip
+  - curl -O https://storage.googleapis.com/flutter_infra_release/releases/stable/linux/flutter_linux_${FLUTTER_VERSION}.zip
+  - unzip -o flutter_linux_${FLUTTER_VERSION}.zip
+  - export PATH="$PATH:$PWD/flutter/bin"
+  - flutter doctor
+
 build:
   stage: build
-  tags:
-    - macos
   script:
-    - flutter config --enable-web
-    - flutter build web --release
+    - flutter pub get
+    - flutter build web
   artifacts:
     paths:
       - build/web
 
 pages:
   stage: deploy
-  tags:
-    - macos
   script:
     - mv build/web public
   artifacts:
     paths:
       - public
   only:
-    - main
\ No newline at end of file
+    - main