breaking: fix `geoJson` parameter

[aMahanna]

Closes https://github.com/ArangoDB-Community/python-arango/issues/234

We are currently using the parameter name ordered to specify whether a Geo Index should be created using GeoJson data-format or not, which can be confusing to users.

This PR just renames the parameter to geo_json

Ref: https://docs.arangodb.com/3.11/index-and-search/indexing/working-with-indexes/geo-spatial-indexes/

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (805425d) 98.33% compared to head (08c4da0) 98.33%.

:exclamation: Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #318 +/- ## ======================================= Coverage 98.33% 98.33% ======================================= Files 26 26 Lines 4201 4201 ======================================= Hits 4131 4131 Misses 70 70 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.