chore: examples/tailwind_axum bumped tailwindcss to 3.4.2.

[martinfrances107]

Just a minor change.

For context tailwindcss version 4 is slated for release later this year.

v4 promises a major improvement in build times...
( The tailwind engine is being ported to RUST!!! )

That will take a more complete adjustment .. but I find
in good software many non-breaking changes will be
slipped into the final v3 release -- so it pays to de-risk
our project by keeping it as tightly in sync as possible.

[martinfrances107]

On sec ... I will update this patch, to be consistent many examples need updating.

[martinfrances107]

On reflection I think this PR is ready to go

The other examples will auto update

For example

cd tailwind_csr
cargo make ci 

argo-make] INFO - Execute Command: "rustup" "run" "nightly-2024-01-29" "trunk" "build"
2024-03-18T18:51:05.841890Z  INFO 🚀 Starting trunk 0.19.1
2024-03-18T18:51:05.844343Z  INFO 📦 starting build
2024-03-18T18:51:05.844791Z  INFO spawned hook sh command_arguments=["-c", "npx tailwindcss -i input.css -o style/output.css"]
2024-03-18T18:51:05.846541Z  INFO spawning hook stage=PreBuild command=sh
Need to install the following packages:
tailwindcss@3.4.1
Ok to proceed? (y) 

[benwis]

LGTM, thanks for the PR!