[Cherry-pick] Ensure the macOS SDK exists at install time (#481)

* Ensure the macOS SDK exists at install time (#480)

* Ensure the macOS SDK exists at install time

* update warning messaging

* remove backticks

(cherry picked from commit 20ceb47)

* Fix SDK logic for 1.1

Drop the `-dev` from the Swiftly version (#432)

Update swiftly version to 1.0.1 in preparation for a patch release (#341

)

1.0.0 release

0.4.0 release

Dev 0.4.0 pre-release

Release updates (#102)

* Update RELEASING.md

* Use "uname -m" as "--machine" doesn't work on Darwin

* Update Dockerfile to use swift 5.10

* Update versions for new release

* Text update

* Update to swift 5.10

Release updates (#102)

* Update RELEASING.md

* Use "uname -m" as "--machine" doesn't work on Darwin

* Update Dockerfile to use swift 5.10

* Update versions for new release

* Text update

* Update to swift 5.10

swiftly-install 0.3.0 (#88)