chore: update dependencies

Update analyzer to ">=6.0.0 <8.0.0" - Update dart_style to ^3.0.1 and use latest language version - Update source_gen to ^2.0.0

Author: IFLyer

Diff for: generator/lib/src/code_builder.dart

@@ -159,7 +159,8 @@ class CodeBuilder extends Builder {
     var code = CodeChunks.objectboxDart(model, imports, pubspec);
 
     try {
-      code = DartFormatter().format(code);
+      code = DartFormatter(languageVersion: DartFormatter.latestLanguageVersion)
+          .format(code);
     } finally {
       // Write the code even after a formatter error so it's easier to debug.
       final codeId = AssetId(

Diff for: generator/pubspec.yaml

@@ -10,13 +10,13 @@ environment:
 
 dependencies:
   objectbox: 4.1.0
-  analyzer: '>=5.2.0 <7.0.0' # 5.1.0 has a bug where DartType.element has been removed.
+  analyzer: '>=6.0.0 <8.0.0' # 5.1.0 has a bug where DartType.element has been removed.
   build: ^2.0.0
   collection: ^1.15.0
-  dart_style: ^2.0.0
+  dart_style: ^3.0.1
   glob: ^2.0.0
   path: ^1.8.0
-  source_gen: ^1.0.0
+  source_gen: ^2.0.0
   pubspec_parse: ^1.0.0
   yaml: ^3.0.0
   http: '>=0.13.5 <2.0.0'