Suppress RSpec/FilePath's offense

This commit suppresses the following `RSpec/FilePath`'s offense:

```console
$ bundle exec rubocop
(snip)

Offenses:

spec/rubocop/ast/rubocop_compatibility_spec.rb:3:1: C: RSpec/FilePath: Spec path should end with rubocop/ast/rubo_cop_compatibility*_spec.rb.
RSpec.describe RuboCop::AST::RuboCopCompatibility do
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

163 files inspected, 1 offense detected
```

.rubocop.yml

@@ -105,6 +105,11 @@ RSpec:
     Expectations:
       - expect_parsing
 
+# Disable `RSpec/FilePath` cop because it has been deprecated:
+# https://docs.rubocop.org/rubocop-rspec/cops_rspec.html#rspecfilepath
+RSpec/FilePath:
+  Enabled: false
+
 RSpec/PredicateMatcher:
   Strict: false