Drop invariant booleans (dart-lang/pubspec_parse#82)

Move to "newer" language check in analysis options

pkgs/pubspec_parse/analysis_options.yaml

diff --git a/pkgs/pubspec_parse/analysis_options.yaml b/pkgs/pubspec_parse/analysis_options.yaml
index 67e23cb..fdc60e0 100644
--- a/pkgs/pubspec_parse/analysis_options.yaml
+++ b/pkgs/pubspec_parse/analysis_options.yaml
@@ -1,8 +1,9 @@
 include: package:lints/recommended.yaml
 
 analyzer:
-  strong-mode:
-    implicit-casts: false
+  language:
+    strict-casts: true
+    strict-inference: true
 
 linter:
   rules:
@@ -21,7 +22,6 @@
     - cascade_invocations
     - comment_references
     - directives_ordering
-    - invariant_booleans
     - join_return_with_assignment
     - lines_longer_than_80_chars
     - literal_only_boolean_expressions

pkgs/pubspec_parse/test/dependency_test.dart

diff --git a/pkgs/pubspec_parse/test/dependency_test.dart b/pkgs/pubspec_parse/test/dependency_test.dart
index da7badc..8fb48e8 100644
--- a/pkgs/pubspec_parse/test/dependency_test.dart
+++ b/pkgs/pubspec_parse/test/dependency_test.dart
@@ -338,7 +338,7 @@
 
   test('git - empty map', () {
     _expectThrows(
-      {'git': {}},
+      {'git': <String, dynamic>{}},
       r'''
 line 5, column 11: Missing key "url". type 'Null' is not a subtype of type 'String' in type cast
   ╷