Dependency build tags not always current

[petehalverson]

Forcing dependencies to use the same build 4a5e2036a215dcb126bcdd51a643ae97e3c43b55 has proven to cause issues:

• Dependency tags aren't always bumped at the same time as the October core
• Packagist sometimes takes a while to update

Instead of strictly adhering to the current October core build, should to something like '<=CURRENT_BUILD'.

This wouldn't resolve the issue encountered when a dependency version is bumped and Packagist isn't current at build time. However, that corner case seems to be mitigated by Automat's build interval.