[Chapel Merge] Bump version button for today's 1.30 release

Branch: refs/heads/main
Revision: 7f919b049bc27d4740c09f520603ac871d178273
Author: bradcray
Link: Bump version button for today's 1.30 release by bradcray · Pull Request #21955 · chapel-lang/chapel · GitHub
Log Message:
Bump version button for today's 1.30 release (#21955)

[trivial, not reviewed]

This is the standard bump to our docs version menu to make 1.30 the
default, reflecting today's release.

Compare: Comparing 3f29d63ab4e89c75c1c2580d31928e40591ae7c0...702339088cda6705f1a44150c9e1f46dfefd07ee · chapel-lang/chapel · GitHub

Diff:
M doc/util/versionButton.php
https://github.com/chapel-lang/chapel/pull/21955.diff