chore(docs) fix initContainers typo

[pallxk]

What this PR does / why we need it:

Fix typo: initcontainers -> initContainers

Which issue this PR fixes

• when using the all lowercase version, initContainers won't get deployed. Fixing the typo to make it easier for begginers.

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] PR is based off the current tip of the main branch.
• [ ] Changes are documented under the "Unreleased" header in CHANGELOG.md
• [ ] Commits follow the Kong commit message guidelines

Notes

commit message follows the format of existing commits.

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