Remove deprecated experimental invariant_booleans lint rule (dart-lang/stream_transform#153)

pkgs/stream_transform/analysis_options.yaml

diff --git a/pkgs/stream_transform/analysis_options.yaml b/pkgs/stream_transform/analysis_options.yaml
index 46018f0..0256c70 100644
--- a/pkgs/stream_transform/analysis_options.yaml
+++ b/pkgs/stream_transform/analysis_options.yaml
@@ -17,7 +17,6 @@
     - cascade_invocations
     - comment_references
     - directives_ordering
-    - invariant_booleans
     - join_return_with_assignment
     - no_adjacent_strings_in_list
     - omit_local_variable_types