Package.swift: Bump CZ to 0.7.0 (#584)

Closes #585

Has a fix for if a uid doesn't exist in /etc/passwd.

Author: dcantah

Package.resolved

@@ -23,7 +23,7 @@ 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 scVersion = "0.6.2"
+let scVersion = "0.7.0"
 
 let package = Package(
     name: "container",