Fix SPM warning introduced in #9124 (#9143)

Author: paulb777

Package.swift

@@ -584,6 +584,7 @@ let package = Package(
         "CHANGELOG.md",
         "CMakeLists.txt",
         "Example/",
+        "LICENSE",
         "Protos/CMakeLists.txt",
         "Protos/Podfile",
         "Protos/README.md",
@@ -648,6 +649,7 @@ let package = Package(
         "CHANGELOG.md",
         "CMakeLists.txt",
         "Example/",
+        "LICENSE",
         "Protos/",
         "README.md",
         "Source/",