Zend certified PHP/Magento developer

SemVer- When bumping the PHP required version in a composer package, say from 7.1 to 7.2, what would be the appropriate package version bump. If the package is at 1.2.3 before the PHP version bump, would 2.0.0 be more appropriate rather than 1.3.0. No other changes to the package/code were made.