dev-master as well as ^1.4 don't pull the latest version.
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Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
The requested package olegkoval/magento2-regenerate-url-rewrites ^1.4 exists as olegkoval/magento2-regenerate-url-rewrites[1.0.0, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.1.1, 1.2.0, 1.2.1, 1.2.2, 1.2.3, 1.3.0, 1.3.1, dev-master] but these are rejected by your constraint.
dev-master as well as ^1.4 don't pull the latest version.
Loading composer repositories with package information Updating dependencies (including require-dev) Your requirements could not be resolved to an installable set of packages.
Problem 1