Suggestion: add option to get commit count across all branches

[eddieyanez]

Useful for branch strategies where staging and production branch off main and the number of commits can vary between the two depending on how merges are executed (e.g. pull request merging one commit at a time in staging vs pull request merging all commits into production once staging is tested will leave the production branch with a lower total number of commits, which is expected).

In this instances, it is not possible to upload a build for a given version with a lower build number as the following error message is returned when uploading "The provided entity includes an attribute with a value that has already been used The bundle version must be higher than the previously uploaded version: ‘823’.". In this specific example, the production branch returned a total commit count of 821, whereas the previously uploaded staging branch had a build number of 823.