Fix a false positive for Performance/RegexpMatch

Follow up rubocop/rubocop-performance#288 (comment).

This PR fixes a false positive for `Performance/RegexpMatch`
when `TargetRubyVersion: 2.3`.

changelog/fix_a_false_positive_for_performance_regexp_match.md

@@ -0,0 +1 @@
+* [#292](https://github.com/rubocop/rubocop-performance/pull/292): Fix a false positive for `Performance/RegexpMatch` when `TargetRubyVersion: 2.3`. ([@koic][])

lib/rubocop/cop/performance/regexp_match.rb

@@ -74,6 +74,9 @@ module Performance
       #   end
       class RegexpMatch < Base
         extend AutoCorrector
+        extend TargetRubyVersion
+
+        minimum_target_ruby_version 2.4
 
         # Constants are included in this list because it is unlikely that
         # someone will store `nil` as a constant and then use it for comparison

spec/rubocop/cop/performance/regexp_match_spec.rb

@@ -423,4 +423,13 @@ def foo
       end
     RUBY
   end
+
+  context 'when Ruby <= 2.3', :ruby23 do
+    it 'does not register an offense when using `String#match` in condition' do
+      expect_no_offenses(<<~RUBY)
+        if 'foo'.match(re)
+        end
+      RUBY
+    end
+  end
 end