Update to oik v4.15.1 for support for PHP 8.4. Tested with WordPress 6.8.

Changes
Changes in oik v4.15.1
| Change | Reference |
|---|---|
| Changed: Update replace_jquery_versions to cater for .min.js | bobbingwide/oik#220 |
| Fixed: Avoid unwanted br tags in pagination links | bobbingwide/oik#242 |
Changes in oik v4.15.0
| Change | Reference |
|---|---|
| Changed: Don’t pass format parameter to bw_get_posts() | bobbingwide/oik#241 |
| Changed: Attempt to reduce the width of select lists in meta boxes | |
| Added: Add bw_theme_field__post_parent() | bobbingwide/oik#238 |
| Changed: don’t exclude the current post in bw_load_noderef and bw_load_noderef2_flat | bobbingwide/oik#239 |
| Added: Invoke bw_post_array filter | bobbingwide/oik#240 |
Tested
- Tested: With WordPress 6.8 and WordPress Multisite
- Tested: With PHP 8.3 & PHP 8.4
- Tested: With PHPUnit 9.6, 10 and 11
