Update builder shim version to 0.6.1 to support default global args (apple#605)

## Type of Change
- [x] Dependency update

## Motivation and Context
A change was made in container-builder-shim to support BuildKit's
default global args
apple/container-builder-shim#44. A new tag of
container-builder-shim was made with this change and this PR updates to
that new tag for container-builder-shim.

Signed-off-by: Kathryn Baldauf <k_baldauf@apple.com>

Author: katiewasnothere

Package.resolved

@@ -22,7 +22,7 @@ import PackageDescription
 
 let releaseVersion = ProcessInfo.processInfo.environment["RELEASE_VERSION"] ?? "0.0.0"
 let gitCommit = ProcessInfo.processInfo.environment["GIT_COMMIT"] ?? "unspecified"
-let builderShimVersion = "0.6.0"
+let builderShimVersion = "0.6.1"
 let scVersion = "0.7.1"
 
 let package = Package(