Unhardcode smithy4sGenerated key in main code

Author: kubukoz

modules/codegen/src/smithy4s/codegen/internals/ModelLoader.scala

@@ -85,7 +85,7 @@ private[codegen] object ModelLoader {
     // Appending all metadata that is not Smithy4s-specific, as well as relevant
     // Smithy4s-related metadata, into the resulting model.
     upstreamModel.getMetadata().asScala.foreach {
-      case (k @ "smithy4sGenerated", _) => ()
+      case (CodegenRecord.METADATA_KEY, _) => ()
       case (k, _) if k.startsWith("smithy4s") =>
         sanitisingModelBuilder.removeMetadataProperty(k)
       case _ => ()

modules/codegen/src/smithy4s/codegen/internals/SmithyResources.scala

@@ -19,6 +19,7 @@ package smithy4s.codegen.internals
 import os.RelPath
 import smithy4s.codegen.BuildInfo
 import smithy4s.codegen.CodegenEntry
+import smithy4s.codegen.CodegenRecord
 
 /**
   * This construct aims at adding metadata information to the classpath to let Smithy4s
@@ -49,7 +50,7 @@ private[smithy4s] object SmithyResources {
     val nsString = namespaces.map(ns => s""""$ns"""").mkString(", ")
     val content = s"""|$$version: "2.0"
                       |
-                      |metadata smithy4sGenerated = [{smithy4sVersion: "$smithy4sVersion", namespaces: [$nsString]}]
+                      |metadata ${CodegenRecord.METADATA_KEY} = [{smithy4sVersion: "$smithy4sVersion", namespaces: [$nsString]}]
                       |""".stripMargin
     val trackingFileEntry = CodegenEntry.FromMemory(trackingFile, content)