Fix unit tests for 3.2 compatibility

Exclude 'Version' from createTranslation():
Causes inconsistencies in Versioned->augmentWrite() because it doesn't write a SiteTree_versions record,
since the Version is already set on the record. In fact, its just copied from the original record,
so there's no SiteTree_versions row correlating to this new record yet.
Updated composer core dep to 3.2
Merge pull request #167 from silverstripe/pulls/3.2-compat

Fix unit tests for 3.2 compatibility