Workflow Proxy classes (added in this PR) are not generated during cache warmup but during application usage instead. This is not recommended for production: https://github.com/Ocramius/ProxyManager/blob/2.9.x/docs/tuning-for-production.md

Steps to reproduce:
0. export APP_ENV=dev
1. git clone https://github.com/ezsystems/ezplatform-ee.git -b 3.1
2. cd ezplatform-ee
3. composer install

Alternative steps for existing installation:
1. rm -rf var/cache/*
2. composer run post-install-cmd

Expected:
The Proxies for Workflow classes are generated somewhere in var/cache/dev/* and there are two Proxy classes: one for EzPlatformWorkflowValueWorkflowMarkingCollection and second for EzPlatformWorkflowValueWorkflowTransitionCollection

Actual:
There are no Proxies for Workflow classes. The Proxies are generated on the fly when a Content Item is created in application, they are created in var/cache/dev/repository/proxy/