Drop invariant_booleans (dart-lang/pub_semver#67)

pkgs/pub_semver/analysis_options.yaml

diff --git a/pkgs/pub_semver/analysis_options.yaml b/pkgs/pub_semver/analysis_options.yaml
index a5aacab..2a5cecd 100644
--- a/pkgs/pub_semver/analysis_options.yaml
+++ b/pkgs/pub_semver/analysis_options.yaml
@@ -28,7 +28,6 @@
     - file_names
     - hash_and_equals
     - implementation_imports
-    - invariant_booleans
     - iterable_contains_unrelated_type
     - join_return_with_assignment
     - list_remove_unrelated_type