fix php deprecation notice in Countries

[DAcodedBEAT]

This resolves the issue shown below:

PHP Deprecated:  Use of "static" in callables is deprecated in develop/ChurchCRM/src/ChurchCRM/data/Countries.php on line 280

Deprecated: Use of "static" in callables is deprecated in develop/ChurchCRM/src/ChurchCRM/data/Countries.php on line 280

Description & Issue number it closes

Screenshots (if appropriate)

How to test the changes?

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[respencer]

Looks good to me.