Pygsheets

* Bug fixes
* added batch value update
* changed default behavior of get_as_df [ref](https://github.com/nithinmurali/pygsheets/issues/423#issuecomment-770520071) **breaking change**

data validation support added
added conditional formatting
metadata support added dankrause
added metadata search dankrause
improved files api support dankrause
Added batch get (now you can fetch multiple ranges in single request)
hyperlink support
Added batchmode in client (Better api merging support)
added support for specifying parent folder name in create
bug fixes

hotfix for worksheet indexing issue. reverted the indexing to start from index 0

**Changed how cell addressing is handled**
Added [Address](https://pygsheets.readthedocs.io/en/staging/address.html#address)
Added [Grid Range](https://pygsheets.readthedocs.io/en/staging/address.html#pygsheets.GridRange)
Now all range implementations use this addressing
Now Datarange supports unbounded ranges

Added update call batching while un-linked
Docs Improved
Other bug fixes

added cell merging and un-merging for a range
added automatically resize rows / columns based on content
added custom http object passing on auhtorization

other bug fixes

Contributors :
daverck