Upgrading samples to flutter_lints, part 1 of n (#804)

testing_app/analysis_options.yaml

@@ -1,4 +1,4 @@
-include: package:pedantic/analysis_options.yaml
+include: package:flutter_lints/flutter.yaml
 
 analyzer:
   strong-mode:
@@ -7,25 +7,15 @@ analyzer:
 
 linter:
   rules:
-    - avoid_types_on_closure_parameters
-    - avoid_void_async
-    - await_only_futures
-    - camel_case_types
-    - cancel_subscriptions
-    - close_sinks
-    - constant_identifier_names
-    - control_flow_in_finally
-    - directives_ordering
-    - empty_statements
-    - hash_and_equals
-    - implementation_imports
-    - non_constant_identifier_names
-    - package_api_docs
-    - package_names
-    - package_prefixed_library_names
-    - test_types_in_equals
-    - throw_in_finally
-    - unnecessary_brace_in_string_interps
-    - unnecessary_getters_setters
-    - unnecessary_new
-    - unnecessary_statements
+    avoid_types_on_closure_parameters: true
+    avoid_void_async: true
+    cancel_subscriptions: true
+    close_sinks: true
+    directives_ordering: true
+    file_names: false
+    package_api_docs: true
+    package_prefixed_library_names: true
+    test_types_in_equals: true
+    throw_in_finally: true
+    unnecessary_statements: true
+    use_key_in_widget_constructors: false