Separate plugins for different Gradle APIs

plugin/gradle81/src/main/kotlin/Gradle2NixPlugin.gradle81.kt

@@ -0,0 +1,7 @@
+package org.nixos.gradle2nix
+
+abstract class Gradle2NixPlugin : AbstractGradle2NixPlugin(
+    GradleCacheAccessFactoryG81,
+    DependencyExtractorApplierG8,
+    ResolveAllArtifactsApplierG8,
+)

plugin/gradle81/src/main/kotlin/GradleCacheAccess.gradle81.kt

@@ -0,0 +1,18 @@
+package org.nixos.gradle2nix
+
+import org.gradle.api.internal.artifacts.ivyservice.ArtifactCachesProvider
+import org.gradle.api.invocation.Gradle
+
+object GradleCacheAccessFactoryG81 : GradleCacheAccessFactory {
+    override fun create(gradle: Gradle): GradleCacheAccess {
+        return GradleCacheAccessG81(gradle)
+    }
+}
+
+class GradleCacheAccessG81(gradle: Gradle) : GradleCacheAccess {
+    private val artifactCachesProvider = gradle.service<ArtifactCachesProvider>()
+
+    override fun useCache(block: () -> Unit) {
+        artifactCachesProvider.writableCacheAccessCoordinator.useCache(block)
+    }
+}