Deprecate adding ancestry to the middle of an STI tree

Provide deprecation warning for has_ancestry in the middle of a tree

Still haven't thought up with a good use case for this.

.github/workflows/run_test_suite.yml

@@ -1,9 +1,9 @@
 name: run-test-suite
 on:
   push:
-    branches: [ master ]
+    branches: [ master, 4-3-stable ]
   pull_request:
-    branches: [ master ]
+    branches: [ master, 4-3-stable ]
 
 jobs:
   test:

lib/ancestry/has_ancestry.rb

@@ -1,6 +1,11 @@
 module Ancestry
   module HasAncestry
     def has_ancestry options = {}
+
+      if base_class != self
+        ActiveSupport::Deprecation.warn("Please move has_ancestry to the root of the STI inheritance tree.")
+      end
+
       # Check options
       raise Ancestry::AncestryException.new(I18n.t("ancestry.option_must_be_hash")) unless options.is_a? Hash
       options.each do |key, value|

test/concerns/sti_support_test.rb

@@ -36,8 +36,10 @@ def test_sti_support_with_from_subclass
       subclass1 = Object.const_set 'SubclassWithAncestry', Class.new(model)
       subclass2 = Object.const_set 'SubclassOfSubclassWithAncestry', Class.new(subclass1)
 
-      # we are defining it one level below the parent ("model" class)
-      subclass1.has_ancestry :ancestry_column => :t1, :counter_cache => true
+      ActiveSupport::Deprecation.silence do
+        # we are defining it one level below the parent ("model" class)
+        subclass1.has_ancestry :ancestry_column => :t1, :counter_cache => true
+      end
 
       # if ancestry is not propogated, then create will fail