[Bot] Use correct token in backport bot (#5654)
The backport bot does currently not trigger the CI when opening a MR,
like here: https://github.com/paritytech/polkadot-sdk/pull/5651
Devs need to push an empty commit manually. Now using a token that will
also trigger the CI.
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Signed-off-by: Oliver Tale-Yazdi <[email protected]>