Fix analysis warnings in docs

docs/pubspec.yaml

@@ -4,6 +4,7 @@ publish_to: none
 
 environment:
   sdk: '>=3.8.0 <4.0.0'
+  flutter: ^3.35.0
 
 dependencies:
   jaspr: ^0.21.5
@@ -35,6 +36,11 @@ dependencies:
   riverpod: ^3.0.2
   jaspr_riverpod: ^0.4.0
   path_provider: ^2.1.4
+  postgres: ^3.5.8
+
+  flutter:
+    sdk: flutter
+  sqlite3_flutter_libs: ^0.5.40
 
 dev_dependencies:
   build_runner: ^2.6.0