Geobr

Minor changes
* Fixed unnecessary warning about internet connection. Closes 200.

**CRAN request**
- Fixed issue to make sure geobr uses suggested packages conditionally

**Minor changes**
- Fixed non-ASCII characters in data `geobr::grid_state_correspondence_table()`

**CRAN request**
- geobr now uses suggested packages conditionally

**New function**
- `read_capitals()` to download either a spatial `sf` object with the location of the municipal seats (sede dos municipios) of state capitals, or a `data.frame` with the names of codes of state capitals. [Closes 243](https://github.com/ipeaGIT/geobr/issues/243)

**Minor changes**
- Update intro vignette to show how to use geobr together with the new [**censobr**](https://ipeagit.github.io/censobr/index.html) sister package.

**Bug fixes**

- fixed bug from conflict between `sf` and `data.table` that was messing with plot extent. [Closes 284](https://github.com/ipeaGIT/geobr/issues/284).
- fixed bug from conflicts between `plotly` and `data.table`. [Closes 279](https://github.com/ipeaGIT/geobr/issues/279).
- fixed bug in `cep_to_state()` function. [Closes 317](https://github.com/ipeaGIT/geobr/issues/317).
- fixed bug in progress bar. [Closes 154](https://github.com/ipeaGIT/geobr/issues/154).
- The `lookup_muni()` and `download_metadata()` functions are now more robust to internet connection failures.

Data release

Minor changes
* Remove packages `crul`and `readr` from geobr dependencies.
* geobr now fails gracefully when server connection times out. Closed 259.

Bug fixes
* Fixed check_connection() that was failing on Linux. Closed 269.