Examples: Use plugin release 0.2.0 and remove Package.resolved (#31)

### Motivation

Release 0.1.0 timed out when uploading to Docker Hub and ECR (#17), so the examples should not allow it to be used.

At the time of the initial release, the examples also needed some dependencies to be pinned to the newest versions to avoid compilation problems with Swift 6.0 or the static Linux SDK.   These problems have now been fixed upstream, so any new build should succeed.

Furthermore, as time goes on, pinning dependencies means that any new compilation problems arising upstream are hidden.   Removing `Package.resolved` means that each clean build will use the newest available dependencies, so new problems upstream will be highlighted.

### Modifications

For each example:
Update `Package.swift` to use the new plugin release.
Remove `Package.resolved`.

### Result

It should be possible to build and publish the examples to Docker Hub or ECR.

### Test Plan

Automated tests still pass; also tested manually with several registries.

Author: euanh

Examples/HelloWorldHummingbird/Package.resolved

@@ -21,7 +21,7 @@ let package = Package(
     platforms: [.macOS(.v14)],
     dependencies: [
         .package(url: "https://github.com/hummingbird-project/hummingbird.git", from: "2.1.0"),
-        .package(url: "https://github.com/apple/swift-container-plugin", from: "0.1.0"),
+        .package(url: "https://github.com/apple/swift-container-plugin", from: "0.2.0"),
     ],
     targets: [
         .executableTarget(name: "hello-world", dependencies: [.product(name: "Hummingbird", package: "hummingbird")])