Increase max retries for GitHub datasets
_The documentation is not available anymore as the PR was closed or merged._
As GitHub recurrently raises connectivity issues, this PR increases the number of max retries to request GitHub datasets, as previously done for GitHub metrics:
- #4063

Note that this is a temporary solution, while we decide when and how to load GitHub datasets from the Hub:
- #4059

Fix #2048

Related to:
- #4051 
- #3210
- #2787 
- #2075
- #2036

CC: @lhoestq 