readme: Replace BUILDING.md link with tutorial link

Author: nicholasbishop

uefi-test-runner/README.md

@@ -5,7 +5,7 @@ be run in a specially-configured QEMU VM. This allows us to test the
 parts of the `uefi` package that depend on a UEFI environment, such as
 various boot services and protocols.
 
-## Prerequisites
+## Requirements
 
 - [QEMU](https://www.qemu.org/): the most recent version of QEMU is recommended.
 - [Python 3](https://www.python.org): at least version 3.6 is required.

uefi/README.md

@@ -49,13 +49,13 @@ For additional information, refer to the [UEFI specification][spec].
 
 ## Building UEFI programs
 
-For instructions on how to create your own UEFI apps, see [BUILDING.md].
+For instructions on how to create your own UEFI apps, see the [tutorial].
 
 The uefi-rs crates currently require some [unstable features].
 The nightly MSRV is currently 2022-08-08.
 
 [unstable features]: https://github.com/rust-osdev/uefi-rs/issues/452
-[BUILDING.md]: https://github.com/rust-osdev/uefi-rs/blob/HEAD/BUILDING.md
+[tutorial]: https://rust-osdev.github.io/uefi-rs/HEAD/tutorial/introduction.html
 
 ## License