PHP 8.2+ - Deprecated '${' string interpolation issue

Problem/Motivation

PHP 8.2 has deprecated ${var} string interpolations https://wiki.php.net/rfc/deprecate_dollar_brace_string_interpolation.

In RoboFile.php::getCurrentConstraint() there are two instances where this style is used. These need to be updated.

Steps to reproduce

Inspect the RoboFile.php code with PHP >= 8.2.x.

Proposed resolution

Update the offending lines of code to not use the (PHP 8.2+) deprecated formatting.

Remaining tasks

MR to follow.

User interface changes

n/a

API changes

n/a

Data model changes

n/a