GH-31412: [Website] Remove support for triggering GitHub Actions apache/arrow-site website deployment workflow when pushing to master

[kevingurney]

Overview

As part of apache/arrow#31142 and in response to the recent rename of the apache/arrow-site repository default branch to main, this pull request removes support for triggering the website deployment workflow (.github/workflows/deploy.yml) on pushes to a branch with the name "master".

Qualification

To qualify these changes, I verified that:

1. Pushing these changes to the main branch of mathworks/arrow-site triggered the deploy.yml workflow as expected.
2. The workflow step "Configure for GitHub Pages on push to main or master branch" has been renamed to "Configure for GitHub Pages on push to main branch"
3. The deploy.yml is no longer being triggered when commits are pushed to a branch named "master".

Future Directions

1. I will follow up with a separate PR to address [Website] Remove mentions of master branch from Apache Arrow website content arrow#20161

Notes

Note: The CI failures in the Build step are unrelated to this change. This is a result of #325, which is being addressed separately.

Closes apache/arrow#31412.

[kevingurney]

I don't think I have the permissions to change it, but I think apache/arrow#31412 should be part of the [Website] component rather than the [Dev] component.

[kevingurney]

@jorisvandenbossche would you be willing to review this PR? Thank you!

[kevingurney]

Note: The CI failures in the Build step are unrelated to this change. This is a result of #325, which is being addressed separately.

[kou]

+1