feat: Update mainline NGINX to 1.29.0

[alessfg]

Proposed changes

Update mainline NGINX to 1.29.0, NJS to 0.9.0, and mainline Alpine Linux to 3.22.

Checklist

Before creating a PR, run through this checklist and mark each as complete:

• I have read the contributing guidelines
• I have signed the F5 Contributor License Agreement (CLA)
• I have run the update.sh script and ensured all entrypoint/Dockerfile template changes have been applied to the relevant image entrypoint scripts & Dockerfiles
• I have tested that the NGINX Docker unprivileged image builds and runs correctly on all supported architectures on an unprivileged environment (check out the README for more details)
• I have updated any relevant documentation (README.md)

[Copilot]

Pull Request Overview

This PR updates the mainline NGINX image versions, along with NJS, Alpine Linux, and related checksum values used across various Dockerfiles and the update script. Key changes include:

• Updating version numbers and corresponding pkgosschecksum values in multiple Dockerfiles.
• Replacing the usage of "greadlink" with "readlink" and "gsed" with "sed" in update.sh.
• Adjusting architecture documentation in README.md.

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
update.sh	Updated version values, removed greadlink in favor of readlink, and updated sed usage.
mainline/debian/Dockerfile	Updated NGINX and NJS version and checksum values.
mainline/debian-perl/Dockerfile	Updated image version and checksum values.
mainline/debian-otel/Dockerfile	Updated image version and checksum values.
mainline/alpine/Dockerfile	Updated image, NJS version, and checksum values.
mainline/alpine-slim/Dockerfile	Updated Alpine image and NGINX version, with corresponding checksum update.
mainline/alpine-perl/Dockerfile	Updated image version and checksum values.
mainline/alpine-otel/Dockerfile	Updated image version and checksum values.
README.md	Updated the list of supported architectures and added note on OTEL images.

Comments suppressed due to low confidence (1)

update.sh:5

• [nitpick] Verify that replacing 'greadlink' with 'readlink' does not alter behavior on environments where GNU readlink features are expected, especially on non-Linux systems.

cd "$(dirname "$(readlink -f "$BASH_SOURCE")")"

[alessfg]

The build is failing due to how the pipeline works. Since the first builds in the sequence did succeed, the rest should work too once the images are actually pushed.