fix a broken link of eksctl (#2510)

[ti-chi-bot]

This is an automated cherry-pick of #2510

What is changed, added, or deleted? (Required)

Close #2509 #2508 #2507 #2506

The documentation page previous found at https://eksctl.io/usage/managing-nodegroups/ has been updated to a new URL https://eksctl.io/usage/nodegroups/. This change was made in https://github.com/eksctl-io/eksctl/commit/aec56df90f29feeead74d1eb5cd643cda907229f

Which TiDB Operator version(s) do your changes apply to? (Required)

• [x] master (the latest development version)
• [x] v1.5 (TiDB Operator 1.5 versions)
• [x] v1.4 (TiDB Operator 1.4 versions)
• [x] v1.3 (TiDB Operator 1.3 versions)
• [x] v1.2 (TiDB Operator 1.2 versions)

What is the related PR or file link(s)?

• This PR is translated from:
• Other reference link(s):

[Oreoxmt]

/approve

[ti-chi-bot[bot]]

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