New file created in Xcode 9.3, <wsname>.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist should it be committed?
From 9.3 release notes, it sounds like you'd want to commit.
Xcode 9.3 adds a new IDEWorkspaceChecks.plist file to a workspace’s shared data, to store the state of necessary workspace checks. Committing this file to source control will prevent unnecessary rerunning of those checks for each user opening the workspace.