add quotes around url in swiftui example

[connorskees-figma]

a user following this readme ran into a problem in which their url contained a &, and so their command was failing. this should hopefully make it clearer that one needs to wrap their url in double quotes

[cerupcat]

Can we get this merged? This was a core piece missing for getting this to work.

[ptomas-figma]

Thank you for your interest in contributing to Code Connect. We'll consider adding the proposed changes to the project, but we're not ready to merge external contributions yet. For further discussion about new features or ideas, please use the Issues tab on this repo.