The BuildKit dockerignore package was migrated to the patternmatcher
repository / module. This patch updates our uses of the BuildKit package
with its new location.
A small local change was made to keep the format of the existing error message,
because the "ignorefile" package is slightly more agnostic in that respect
and doesn't include ".dockerignore" in the error message.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Sebastiaan van Stijn