add dependency on adaptive_theme

pubspec.lock

@@ -1,6 +1,13 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  adaptive_theme:
+    dependency: "direct main"
+    description:
+      name: adaptive_theme
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.3.0"
   alice:
     dependency: "direct main"
     description:

pubspec.yaml

@@ -18,6 +18,7 @@ environment:
 
 dependencies:
   alice: ^0.2.4
+  adaptive_theme: ^2.3.0
   animate_do: ^2.0.0
   archive: ^3.1.2
   background_fetch: ^1.0.1