Updating creating DevTools/Project leads to initial error

[Fr33chen]

When creating a new project com.woltlab.wcf will be added as requirement (without version number) and as excluded package (with version 6). This leads to an error "If required packages are added as conflicting packages...". https://github.com/WoltLab/WCF/blob/82d0cebf9ea504bcc0e37b0b0b5bd089f0680c1b/wcfsetup/install/files/lib/acp/form/DevtoolsProjectAddForm.class.php#L591 Furthermore, the requirement can't be changed (it must be deleted and added new with version number). Maybe the required wcf-version should be part of the project add form.