Add a testcase for Regex

tests/test_regex.py

@@ -0,0 +1,10 @@
+from tests.helper import ExternalVersionTestCase
+
+
+class RegexTest(ExternalVersionTestCase):
+    def test_regex(self):
+        self.assertEqual(self.sync_get_version("example", {
+            "url": "https://httpbin.org/get",
+            "regex": '"User-Agent": "(\w+)"',
+            "user_agent": "Meow",
+        }), "Meow")