[JGit] Sandbox repositories with LFS fail authentication

[fbiville]

This is a consequence of https://bugs.eclipse.org/bugs/show_bug.cgi?id=535814.

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 - Update for sandbox https://github.com/neo4j-graph-examples/yelp.git failed with the following error:
java.io.IOException: org.eclipse.jgit.api.errors.JGitInternalException: org.eclipse.jgit.api.errors.FilterFailedException: Execution of filter command 'git-lfs smudge -- 'data/yelp-35.dump'' on file 'data/yelp-35.dump' failed with return code '2', message on stderr: 'Downloading data/yelp-35.dump (915 MB)
	fatal: could not read Username for 'https://github.com': No such device or address
	Error downloading object: data/yelp-35.dump (d73d2c3): Smudge error: Error downloading data/yelp-35.dump (d73d2c35203ec855e09100e53d6607172920769e73b78069cc9c6bdf8b384a26): batch response: Git credentials for https://github.com/neo4j-graph-examples/yelp.git not found.
	
	Errors logged to /tmp/sandbox-updater8621491578302407309/yelp/.git/lfs/logs/20210702T095131.41546237.log
	Use `git lfs logs last` to view the log.
	'
 - Update for sandbox https://github.com/neo4j-graph-examples/twitch.git failed with the following error:
java.io.IOException: org.eclipse.jgit.api.errors.TransportException: Rejected by "pre-push" hook.
	fatal: could not read Username for 'https://github.com': No such device or address
	Git credentials for https://github.com/neo4j-graph-examples/twitch.git not found.
	
---

	at com.neo4j.sandbox.updater.BatchUpdater.updateBatch(BatchUpdater.java:93) ~[classes/:na]
	at com.neo4j.sandbox.Main.run(Main.java:19) ~[classes/:na]
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:791) ~[spring-boot-2.5.2.jar:2.5.2]
	... 5 common frames omitted

[fbiville]

432bb75 (+ aee2e76 and f2a4076) reinstate the Git CLI-based implementation, so that LFS repo can be updated again in CI, thanks @jexp for the help.

I'm keeping this issue open since I'd like to go back to the JGit-based implementation once the aforementioned ticket is resolved.