fix: ignore merge messages with text after newline

* fix(is-ignored): regex not work with newline and extra characters

* test(is-ignored): test for newlines with extra characters

Author: dabit1

@commitlint/is-ignored/src/index.js

@@ -3,7 +3,7 @@ import semver from 'semver';
 const WILDCARDS = [
 	c =>
 		c.match(
-			/^((Merge pull request)|(Merge (.*?) into (.*?)|(Merge branch (.*?)))(?:\r?\n)*$)/
+			/^((Merge pull request)|(Merge (.*?) into (.*?)|(Merge branch (.*?)))(?:\r?\n)*$)/m
 		),
 	c => c.match(/^(R|r)evert (.*)/),
 	c => c.match(/^(fixup|squash)!/),

@commitlint/is-ignored/src/index.test.js

@@ -61,6 +61,11 @@ test('should return true for merged PRs', t => {
 	t.true(isIgnored('Merge pull request #369'));
 });
 
+test('should return true for branch merges with newline characters and more characters after it', t => {
+	t.true(isIgnored("Merge branch 'ctrom-YarnBuild'\n "));
+	t.true(isIgnored("Merge branch 'ctrom-YarnBuild'\r\n # some comment"));
+});
+
 test('should return true for revert commits', t => {
 	t.true(
 		isIgnored(