cdc add rolling upgrade document.

[3AceShowHand]

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What is changed, added or deleted? (Required)

Refine ticdc docs, including adding description about how to manage ticdc using TiUP and ticdc rolling upgrade.

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• master (the latest development version)
• v6.2 (TiDB 6.2 versions)
• v6.1 (TiDB 6.1 versions)
• v5.4 (TiDB 5.4 versions)
• v5.3 (TiDB 5.3 versions)
• v5.2 (TiDB 5.2 versions)
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[ti-chi-bot]

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[fubinzh]

transfer-timeout 参数对 扩容 无效么？

[3AceShowHand]

扩容之前，不需要 transfer。扩容之后，会自动进行平衡。

[ti-chi-bot]

@3AceShowHand: PR needs rebase.

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[ti-chi-bot]

@3AceShowHand: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-verify	07781ab	link	true	/test pull-verify

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