[Polaris Office Android] Update history for June 2022

[Polaris Office Cloud]

Data: 2022-06-13 (Korean Time)

Version: 9.6.8

- Now support for adding new types of fonts.
- Enhanced annotations and features for PDF documents.
- Able to open and save new documents under different name when editing a TXT document.
- Fixed the slow scrolling issue in PDF documents.