How to delete Swift Package Dependency in Xcode 11?

1. Open Xcode
2. Select your project
3. Look at the top middle
4. Select Swift Package Manager menu

You'll be able to manage your packages (add / remove)

Swift Package Manager(SPM) Dependency

Add dependency

1. Project Settings contains information about dependencies. 
2. File -> Swift Packages -> Add Package Dependency...
3. Target -> General -> Frameworks, Libraries, and Embedded Content -> Add Items -> Add Other... -> Add Package Dependency...

Target Settings includes product from dependency

Edit dependency

To edit URL you can edit .pbxproj with repositoryURL

Delete dependency

Project -> Packages -> <Select dependency> -> -

[Local Swift Package Manager(SPM)]
[iOS Dependency manager]

In addition to Pierre's answer, this was driving me crazy, I had a sub project that I was editing, I forgot about that (it was in a subfolder). Even though I removed it in the "Swift Packages" pane it kept coming back. Removing that sub folder reference made sure the PM dependencies went away.