Drop SwiftMessages SwiftPM dependency

Trio.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -1,5 +1,5 @@
 {
-  "originHash" : "1e72c1cdf8ea5ec9fe527ebfab01ea55fca9e8651fe3252338fd3d4ea2cb327a",
+  "originHash" : "29c2d0190b27ae86bc9534bbc8a3bba9693842515e38f5e89a3dbf80573f962f",
   "pins" : [
     {
       "identity" : "abseil-cpp-binary",
@@ -263,15 +263,6 @@
       }
     },
     {
-      "identity" : "swiftmessages",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/SwiftKickMobile/SwiftMessages",
-      "state" : {
-        "revision" : "62e12e138fc3eedf88c7553dd5d98712aa119f40",
-        "version" : "9.0.9"
-      }
-    },
-    {
       "identity" : "swinject",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/Swinject/Swinject",