[MRESOLVER-411] Update to Maven 4.0.0-alpha-8 (#350)

And get rid of last TODO. Note: this issue is refurbished from "Update to Maven 4.0.0-alpha-7".

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https://issues.apache.org/jira/browse/MRESOLVER-411

maven-resolver-supplier/src/main/java/org/eclipse/aether/supplier/RepositorySystemSupplier.java

@@ -457,13 +457,9 @@ protected VersionScheme getVersionScheme() {
     protected Map<String, MetadataGeneratorFactory> getMetadataGeneratorFactories() {
         // from maven-resolver-provider
         HashMap<String, MetadataGeneratorFactory> result = new HashMap<>();
-        // result.put(PluginsMetadataGeneratorFactory.NAME, new PluginsMetadataGeneratorFactory());
-        // result.put(VersionsMetadataGeneratorFactory.NAME, new VersionsMetadataGeneratorFactory());
-        // result.put(SnapshotMetadataGeneratorFactory.NAME, new SnapshotMetadataGeneratorFactory());
-        // TODO: Fix this once MNG-7874 done and released as Maven 4.0.0-alpha-8
-        result.put("plugins", new PluginsMetadataGeneratorFactory());
-        result.put("versions", new VersionsMetadataGeneratorFactory());
-        result.put("snapshot", new SnapshotMetadataGeneratorFactory());
+        result.put(PluginsMetadataGeneratorFactory.NAME, new PluginsMetadataGeneratorFactory());
+        result.put(VersionsMetadataGeneratorFactory.NAME, new VersionsMetadataGeneratorFactory());
+        result.put(SnapshotMetadataGeneratorFactory.NAME, new SnapshotMetadataGeneratorFactory());
         return result;
     }
 

pom.xml

@@ -96,7 +96,7 @@
     <guiceVersion>6.0.0</guiceVersion>
     <slf4jVersion>1.7.36</slf4jVersion>
     <!-- used by supplier and demo only -->
-    <mavenVersion>4.0.0-alpha-7</mavenVersion>
+    <mavenVersion>4.0.0-alpha-8</mavenVersion>
     <minimalMavenBuildVersion>[3.8.8,)</minimalMavenBuildVersion>
     <minimalJavaBuildVersion>[11.0.16,)</minimalJavaBuildVersion>
     <project.build.outputTimestamp>2023-10-10T21:40:45Z</project.build.outputTimestamp>