[BUG] Use Node 20 warning

[nathanchase]

Describe the bug
When using this action, this warning appears:
Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: arddluma/cloudflare-pages-slack-notification@v4. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

Expected behavior
The action should not cause this warning to appear, by way of using Node 20.

Additional context
https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

[nathanchase]

Should just be a matter of updating

cloudflare-pages-slack-notification/action.yml

Line 41 in 4d5b0d3

using: 'node16'

to 'node20' ?

[arddluma]

Should just be a matter of updating

cloudflare-pages-slack-notification/action.yml

Line 41 in 4d5b0d3

using: 'node16'

to 'node20' ?

hey yes, and verifying if existing packages work.
I will publish a patch today hopefully! thank you