Drop invariant bools lint (#53)

diff --git a/analysis_options.yaml b/analysis_options.yaml
index 821eb57..3394eae 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -13,7 +13,6 @@
     - cancel_subscriptions
     - comment_references
     - directives_ordering
-    - invariant_booleans
     - no_adjacent_strings_in_list
     - omit_local_variable_types
     - only_throw_errors