Implement/test LOLWUT command (#1568)

* Implement/test LOLWUT command

https://redis.io/commands/lolwut

This is a lot of fun to play with:

```python
>>> from redis import Redis
>>> redis = Redis()
>>> print(redis.lolwut(5, 6, 7, 8).decode('utf-8'))
⣴⣶⣶⣶⣶⡆
⣿⣿⣿⣿⣿⡇
⠹⡿⠟⣿⡿⠃
⠀⠀⠀⠀⠀⠀
Georg Nees - schotter, plotter on paper, 1968. Redis ver. 6.0.10

>>> print(redis.lolwut(5, 6, 7, 8).decode('utf-8'))
⢰⣶⣶⣶⣶⡆
⢿⣿⣿⣿⣿⠁
⠸⡿⢿⠿⡿⠃
⠀⠀⠀⠀⠀⠀
Georg Nees - schotter, plotter on paper, 1968. Redis ver. 6.0.10

>>> print(redis.lolwut(5, 6, 7, 8).decode('utf-8'))
⢰⣶⣶⣶⣶⡆
⣸⣿⣿⣻⣿⡅
⠿⡿⠻⠿⠿⠁
⠀⠀⠀⠀⠀⠀
Georg Nees - schotter, plotter on paper, 1968. Redis ver. 6.0.10

>>>
```

* Add link to LOLWUT command documentation

Co-authored-by: Chayim <chayim@users.noreply.github.com>

* Skip LOLWUT unit test for Redis < 5.0.0

The `LOLWUT` command was introduced in Redis 5.0.0:
https://redis.io/commands/lolwut

Co-authored-by: Chayim <chayim@users.noreply.github.com>

Author: brainix

redis/commands.py

@@ -523,6 +523,15 @@ def lastsave(self):
         """
         return self.execute_command('LASTSAVE')
 
+    def lolwut(self, *version_numbers):
+        """Get the Redis version and a piece of generative computer art
+        See: https://redis.io/commands/lolwut
+        """
+        if version_numbers:
+            return self.execute_command('LOLWUT VERSION', *version_numbers)
+        else:
+            return self.execute_command('LOLWUT')
+
     def migrate(self, host, port, keys, destination_db, timeout,
                 copy=False, replace=False, auth=None):
         """

tests/test_commands.py

@@ -531,6 +531,14 @@ def test_info(self, r):
     def test_lastsave(self, r):
         assert isinstance(r.lastsave(), datetime.datetime)
 
+    @skip_if_server_version_lt('5.0.0')
+    def test_lolwut(self, r):
+        lolwut = r.lolwut().decode('utf-8')
+        assert 'Redis ver.' in lolwut
+
+        lolwut = r.lolwut(5, 6, 7, 8).decode('utf-8')
+        assert 'Redis ver.' in lolwut
+
     def test_object(self, r):
         r['a'] = 'foo'
         assert isinstance(r.object('refcount', 'a'), int)