docs(README): update roadmap in README.md

Signed-off-by: Deep Panchal <deep302001@gmail.com>

README.md

@@ -194,7 +194,7 @@ cargo test
  - [ ] Move page to another book [#60](https://github.com/deepanchal/dnote-tui/issues/60)
  - [x] Delete a book's page [#51](https://github.com/deepanchal/dnote-tui/issues/51)
  - [x] Delete a book and all its pages [#52](https://github.com/deepanchal/dnote-tui/issues/52)
- - [ ] Rename book with popup input field [#59](https://github.com/deepanchal/dnote-tui/issues/59)
+ - [x] Rename book with popup input field [#59](https://github.com/deepanchal/dnote-tui/issues/59)
  - [ ] Search and Navigation
  - [ ] Find note within a book [#61](https://github.com/deepanchal/dnote-tui/issues/61)
  - [ ] Global note search [#47](https://github.com/deepanchal/dnote-tui/issues/47)