Update build.yml

[thePsguy]

• Add set -o pipefail so errors surface correctly
• Update to build with a generic iOS destination

---

name: Pull request
about: Create a pull request
label: 'triage me'

Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:

• Make sure to open a GitHub issue as a bug/feature request before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

Fixes #<issue_number_goes_here> 🦕