Fix EZP-22415: Upgrade dependency to stash bundle to 0.3

This upgrade allows to fix EZP-20923: Fatal errors on Windows stash fails with mkdir(): Invalid path
as Stash-Bundle 0.3 exposes hash algorithm change (use crc32 instead of md5 on Windows)
EZP-22415: Removed @covers in tests
Merge pull request #771 from ezsystems/fix_EZP-22415_upgradeStashBundle

Fix EZP-22415 Upgrade stash bundle