[KYUUBI apache#4340] Bump up markdown version from 3.3.7 to 3.4.1

### _Why are the changes needed?_

Bump up markdown version from 3.3.7 to 3.4.1, the sphinx-markdown-tables has been upgraded to 0.0.17 in which the regression is resolved. It now conflicts with markdown 3.3.7

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [x] [Run test](https://kyuubi.readthedocs.io/en/master/develop_tools/testing.html#running-tests) locally before make a pull request

Closes apache#4340 from yaooqinn/markdown.

Closes apache#4340

da950a7 [Kent Yao] Bump up markdown version form 3.3.7 to 3.4.1

Authored-by: Kent Yao <yao@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>

docs/requirements.txt

@@ -17,8 +17,7 @@
 # under the License.
 #
 
-# we shall bypass markdown-3.4.1, see details in KYUUBI-3126
-markdown==3.3.7
+markdown==3.4.1
 recommonmark==0.7.1
 sphinx==4.5.0
 sphinx-book-theme==0.3.3