Fix a false negartive for Performance/RegexpMatch

Follow up rubocop/rubocop#6965.

This PR fixes a false negartive for `Performance/RegexpMatch`
when using RuboCop 0.68 or higher.

```ruby
# example.rb
def foo
  if /re/.match(foo, 1)
    do_something
  end
end
```

## RuboCop 0.67

RuboCop 0.67 warns.

```console
% rubocop _0.67.2_ --only Performance/RegexpMatch
Inspecting 1 file
C

Offenses:

example.rb:2:6: C: Performance/RegexpMatch: Use match? instead of match
when MatchData is not used.
  if /re/.match(foo, 1)
       ^^^^^^^^^^^^^^^^^^

1 file inspected, 1 offense detected
```

## RuboCop 0.68 (Before)

RuboCop 0.68 does not warn. This is a false negative.

```console
% rubocop _0.68.1_ --only Performance/RegexpMatch --require
rubocop-performance
Inspecting 1 file
.

1 file inspected, no offenses detected
```

## RuboCop 0.68 (After)

This PR fixes a false negative.

```console
% rubocop --only Performance/RegexpMatch --require rubocop-performance
Inspecting 1 file
C

Offenses:

example.rb:2:6: C: Performance/RegexpMatch: Use match? instead of match
when MatchData is not used.
  if /re/.match(foo, 1)
       ^^^^^^^^^^^^^^^^^^

1 file inspected, 1 offense detected
```

This fix uses the following `<>` node pattern notation introduced in
RuboCop 0.68, so it supports Ruby version 0.68 or higher.
rubocop/rubocop#6965

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### Bug fixes
+
+* [#47](https://github.com/rubocop-hq/rubocop-performance/pull/47): Fix a false negartive for `Performance/RegexpMatch` when using RuboCop 0.68 or higher. ([@koic][])
+
 ## 1.1.0 (2019-04-08)
 
 ### Changes

lib/rubocop/cop/performance/regexp_match.rb

@@ -86,8 +86,8 @@ class RegexpMatch < Cop
 
         def_node_matcher :match_method?, <<-PATTERN
           {
+            (send _recv :match _ <int ...>)
             (send _recv :match _)
-            (send _recv :match _ (int ...))
           }
         PATTERN
 

rubocop-performance.gemspec

@@ -29,6 +29,6 @@ Gem::Specification.new do |s|
     'bug_tracker_uri' => 'https://github.com/rubocop-hq/rubocop-performance/issues'
   }
 
-  s.add_runtime_dependency('rubocop', '>= 0.67.0')
+  s.add_runtime_dependency('rubocop', '>= 0.68.0')
   s.add_development_dependency('simplecov')
 end