Fix self-hosting

model/src/main/kotlin/org/nixos/gradle2nix/Impl.kt

@@ -49,6 +49,7 @@ data class DefaultGradle(
 @JsonClass(generateAdapter = true)
 data class DefaultProject(
     override val name: String,
+    override val version: String,
     override val path: String,
     override val projectDir: String,
     override val buildscriptDependencies: DefaultDependencies,
@@ -57,6 +58,7 @@ data class DefaultProject(
 ) : Project, Serializable {
     constructor(model: Project) : this(
         model.name,
+        model.version,
         model.path,
         model.projectDir,
         DefaultDependencies(model.buildscriptDependencies),

model/src/main/kotlin/org/nixos/gradle2nix/Model.kt

@@ -22,6 +22,7 @@ interface Gradle {
 
 interface Project {
     val name: String
+    val version: String
     val path: String
     val projectDir: String
     val buildscriptDependencies: Dependencies