Make access modifiers public for users of the package. (#8086)

Change a few access modifiers to public.

### Motivation:

As a user of the package, I am trying to access these properties.

Author: shawnhyam

Sources/PackageGraph/Resolution/ResolvedPackage.swift

@@ -40,7 +40,7 @@ public struct ResolvedPackage {
     public let products: [ResolvedProduct]
 
     /// The enabled traits of this package.
-    package let enabledTraits: Set<String>
+    public let enabledTraits: Set<String>
 
     /// The dependencies of the package.
     public let dependencies: [PackageIdentity]

Sources/SPMBuildCore/Plugins/PluginInvocation.swift

@@ -34,10 +34,10 @@ public enum PluginAction {
 }
 
 public struct PluginTool {
-    let path: AbsolutePath
-    let triples: [String]?
+    public let path: AbsolutePath
+    public let triples: [String]?
 
-    init(path: AbsolutePath, triples: [String]? = nil) {
+    public init(path: AbsolutePath, triples: [String]? = nil) {
         self.path = path
         self.triples = triples
     }

Sources/Workspace/Workspace.swift

@@ -1237,6 +1237,22 @@ extension Workspace {
             completion(result)
         }
     }
+
+    public func changeSigningEntityFromVersion(
+        package: PackageIdentity,
+        version: Version,
+        signingEntity: SigningEntity,
+        origin: SigningEntity.Origin,
+        observabilityScope: ObservabilityScope
+    ) throws {
+        try self.registryClient.changeSigningEntityFromVersion(
+            package: package,
+            version: version,
+            signingEntity: signingEntity,
+            origin: origin,
+            observabilityScope: observabilityScope
+        )
+    }
 }
 
 extension Workspace {