Bump version and changelog for v3.74.2

[wolfeidau]

v3.74.2 (2024-07-16)

Full Changelog

Added

• Reject more secrets #2884 (@DrJosh9000)
• Introduce riscv64 architecture #2877 (@TimePrinciple)
• Include repo name in Packages image path #2871 (@swebb)

Fixed

• SUP-2343: remove "retry" example from "buildkite-agent step get" as not valid #2879 (@tomowatt)
• Fix some common artifact download bugs #2878 (@DrJosh9000)
• Fix the OIDC login for Packages #2875 (@swebb)
• Fix the Packages registry name #2874 (@swebb)
• Fix image name when pushing to Buildkite packages #2870 (@swebb)

Internal

• Update LICENSE.txt #2885 (@wooly)
• Remove Packagecloud agent publish steps from agent pipeline #2873 (@tommeier)
• Release Docker images on Buildkite Packages #2837 (@swebb)
• Dependabot updates: #2888, #2887, #2882, #2883, #2880 (@dependabot[bot])

[DrJosh9000]

1. I think this is release is more of a 3.75.0 than a 3.74.2. That's my read of the vibes, happy to discuss.
2. It occurred to me when reading this that Reject more secrets #2884 could be a breaking change. Anyone with --reject-secrets and pipelines with secret-like vars would upload with 3.74.1, but not with this release. I think we should at least call that out as a change.
3. Don't forget the version/VERSION file!

[wolfeidau]

@DrJosh9000 yeah I will open a new PR