bump pytables to 3.5.1 #24839
- [x] closes #24839
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

PyTables 3.5.1 was released on March 14, 2019. And it offers better support for np16.

can you add a whatsnew bug fix note (I/O) that the issue is fixed in the OP; can merge after that. thanks @fangchenli 