Remove hardcoded variables, like 'git config user.email "[email protected]"' or 'git config user.name "updatebot"'

[MaxPeal]

Remove hard-coded variables, without its not possible to fork, update, test and create a PR for an update. like this: https://github.com/jauderho/dockerfiles/blob/de11454352d5fbf069a794f102456c3bd9a7f87b/scripts/updateDockerImages.sh#L61-L63 https://github.com/jauderho/dockerfiles/blob/de11454352d5fbf069a794f102456c3bd9a7f87b/scripts/updatePythonDeps.sh#L9-L10