Breaking Changes

• Dropped support for Squeak 5.3

What's Changed

• Expanded the testcase for GRPlatform>>secureHashFor: by @jbrichau in #182
• Squeak fixes by @marschall in #185 and #188
• PackageManifest class added to Squeak by @marschall to fix #187

Full Changelog: v1.18.2...1.19.0