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>
As it's just an alias for filepath.IsAbs. Also added a normalize step in
TrimBuildFilesFromExcludes, so that callers are not _required_ to first
normalize the path.
We are considering deprecating and/or removing this function in the archive
package, so removing it in the cli code helps transitioning if we decide to
deprecate and/or remove it.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>