updated project style guidelines

analysis_options.yaml

@@ -28,6 +28,13 @@ linter:
     prefer_relative_imports: true
     unnecessary_lambdas: true
     prefer_single_quotes: true
+    prefer_if_elements_to_conditional_expressions: true
+    prefer_expression_function_bodies: true
+    omit_local_variable_types: true
+    eol_at_end_of_file: true
+    cast_nullable_to_non_nullable: true
+    avoid_void_async: true
+    avoid_multiple_declarations_per_line: true
 
 # Additional information about this file can be found at
 # https://dart.dev/guides/language/analysis-options