Add symlink for ios 13 simulator

[kerrmarin]

No description provided.

[kerrmarin]

I can't seem to find the simulators on the CI machines. The instructions on actions/runner-images#551 don't seem to work anymore. I think we have 3 options:

• Keep trying to find the simulators in case I'm doing something stupid
• Use DEVELOPER_DIR to select a different Xcode instead but don't use the matrix
• Give up and just test on latest until there is a clear way of doing this

[deanWombourne]

Option 3 - this isn't worth this much of your time :)