Fix .gitignore file

Flutter.gitignore

@@ -1,5 +1,6 @@
 # Miscellaneous
 *.class
+*.lock
 *.log
 *.pyc
 *.swp
@@ -16,25 +17,58 @@
 .idea/
 
 # Visual Studio Code related
-.vscode/
+.classpath
+.project
+.settings/
+.vscode/*
+
+# Flutter repo-specific
+/bin/cache/
+/bin/internal/bootstrap.bat
+/bin/internal/bootstrap.sh
+/bin/mingit/
+/dev/benchmarks/mega_gallery/
+/dev/bots/.recipe_deps
+/dev/bots/android_tools/
+/dev/devicelab/ABresults*.json
+/dev/docs/doc/
+/dev/docs/flutter.docs.zip
+/dev/docs/lib/
+/dev/docs/pubspec.yaml
+/dev/integration_tests/**/xcuserdata
+/dev/integration_tests/**/Pods
+/packages/flutter/coverage/
+version
+analysis_benchmark.json
+
+# packages file containing multi-root paths
+.packages.generated
 
 # Flutter/Dart/Pub related
 **/doc/api/
 .dart_tool/
 .flutter-plugins
+.flutter-plugins-dependencies
+**/generated_plugin_registrant.dart
 .packages
-.pub-cache/
+.pub-preload-cache/
 .pub/
-/build/
+build/
+flutter_*.png
+linked_*.ds
+unlinked.ds
+unlinked_spec.ds
 
 # Android related
 **/android/**/gradle-wrapper.jar
-**/android/.gradle
+.gradle/
 **/android/captures/
 **/android/gradlew
 **/android/gradlew.bat
 **/android/local.properties
 **/android/**/GeneratedPluginRegistrant.java
+**/android/key.properties
+*.jks
 
 # iOS/XCode related
 **/ios/**/*.mode1v3
@@ -53,18 +87,47 @@
 **/ios/**/profile
 **/ios/**/xcuserdata
 **/ios/.generated/
+**/ios/Flutter/.last_build_id
 **/ios/Flutter/App.framework
 **/ios/Flutter/Flutter.framework
+**/ios/Flutter/Flutter.podspec
 **/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/ephemeral
 **/ios/Flutter/app.flx
 **/ios/Flutter/app.zip
 **/ios/Flutter/flutter_assets/
+**/ios/Flutter/flutter_export_environment.sh
 **/ios/ServiceDefinitions.json
 **/ios/Runner/GeneratedPluginRegistrant.*
 
+# macOS
+**/Flutter/ephemeral/
+**/Pods/
+**/macos/Flutter/GeneratedPluginRegistrant.swift
+**/macos/Flutter/ephemeral
+**/xcuserdata/
+
+# Windows
+**/windows/flutter/generated_plugin_registrant.cc
+**/windows/flutter/generated_plugin_registrant.h
+**/windows/flutter/generated_plugins.cmake
+
+# Linux
+**/linux/flutter/generated_plugin_registrant.cc
+**/linux/flutter/generated_plugin_registrant.h
+**/linux/flutter/generated_plugins.cmake
+
+# Coverage
+coverage/
+
+# Symbols
+app.*.symbols
+
 # Exceptions to above rules.
 !**/ios/**/default.mode1v3
 !**/ios/**/default.mode2v3
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+!/dev/ci/**/Gemfile.lock
+!.vscode/settings.json