Installing Homebrew formula with --head does not work

[philwebb]

See build.head section

[wilkinsona]

Things don't even get as far as trying to build with Maven due to an attempt to use the master branch:

 brew install spring-boot --HEAD
==> Fetching spring-io/tap/spring-boot
==> Cloning https://github.com/spring-projects/spring-boot.git
Cloning into '/Users/awilkinson/Library/Caches/Homebrew/spring-boot--git'...
fatal: Remote branch master not found in upstream origin
Error: spring-boot: Failed to download resource "spring-boot"
Failure while executing; `git clone --branch master -c advice.detachedHead=false https://github.com/spring-projects/spring-boot.git /Users/awilkinson/Library/Caches/Homebrew/spring-boot--git` exited with 128. Here's the output:
Cloning into '/Users/awilkinson/Library/Caches/Homebrew/spring-boot--git'...
fatal: Remote branch master not found in upstream origin

[wilkinsona]

Moving to 3.0.x as we only update the Homebrew tap for the latest GA release.