Fix deprecated ${} string interpolation for PHP8.2

[leoshtika]

Hi everyone!

After updating to PHP8.2, when running for example ReadRegistersBuilder::newReadHoldingRegisters()->allFromArray($requests)->build(); I am getting a PHP Deprecated Warning 'ErrorException' with message 'Using ${var} in strings is deprecated, use {$var} instead'

I discovered that ${} string interpolation was deprecated in PHP8.2 https://www.php.net/releases/8.2/en.php#deprecations_and_bc_breaks

I will upload a patch that fixes this problem shortly!

Environment:

• OS: Ubuntu 22.04
• PHP version: 8.2.8
• Library version: 3.4.0
• My error_reporting is set to E_ALL (since PHP8 this is the default value, prior PHP8 was E_ALL & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED).