Revert "Force the default version of all supported Hibernate ORM dialects"

We'd rather rely on ORM defaults where possible.

This reverts commit d3b0fd7e0c5dcc860be28e620830a4292550361b.

Author: yrodiere

extensions/datasource/runtime/src/main/java/io/quarkus/datasource/runtime/DataSourceBuildTimeConfig.java

@@ -41,7 +41,7 @@ public class DataSourceBuildTimeConfig {
      * or simply a warning in case the database cannot be reached.
      *
      * The default for this property is specific to each extension;
-     * the Hibernate ORM extension will default to the oldest version supported in Quarkus.
+     * the Hibernate ORM extension will default to the oldest version it supports.
      *
      * @asciidoclet
      */

extensions/hibernate-orm/deployment/src/main/java/io/quarkus/hibernate/orm/deployment/HibernateOrmProcessor.java

@@ -178,9 +178,9 @@ public final class HibernateOrmProcessor {
     void registerHibernateOrmMetadataForCoreDialects(
             BuildProducer<DatabaseKindDialectBuildItem> producer) {
         producer.produce(new DatabaseKindDialectBuildItem(DatabaseKind.DB2,
-                "org.hibernate.dialect.DB2Dialect", DialectVersions.Defaults.DB2));
+                "org.hibernate.dialect.DB2Dialect"));
         producer.produce(new DatabaseKindDialectBuildItem(DatabaseKind.DERBY,
-                "org.hibernate.dialect.DerbyDialect", DialectVersions.Defaults.DERBY));
+                "org.hibernate.dialect.DerbyDialect"));
         producer.produce(new DatabaseKindDialectBuildItem(DatabaseKind.H2,
                 // Using our own default version is extra important for H2
                 // See https://github.com/quarkusio/quarkus/issues/1886
@@ -194,7 +194,7 @@ void registerHibernateOrmMetadataForCoreDialects(
         producer.produce(new DatabaseKindDialectBuildItem(DatabaseKind.ORACLE,
                 "org.hibernate.dialect.OracleDialect", DialectVersions.Defaults.ORACLE));
         producer.produce(new DatabaseKindDialectBuildItem(DatabaseKind.POSTGRESQL,
-                "org.hibernate.dialect.PostgreSQLDialect", DialectVersions.Defaults.POSTGRESQL));
+                "org.hibernate.dialect.PostgreSQLDialect"));
     }
 
     @BuildStep

extensions/hibernate-orm/runtime/src/main/java/io/quarkus/hibernate/orm/runtime/config/DialectVersions.java

@@ -16,13 +16,10 @@ public final class DialectVersions {
     public static final class Defaults {
 
         // The following constants must be at least equal to the default dialect version in Hibernate ORM
-        public static final String DB2 = "10.5";
-        public static final String DERBY = "10.14";
         public static final String MARIADB = "10.6";
         public static final String MSSQL = "13"; // 2016
         public static final String MYSQL = "8";
         public static final String ORACLE = "12";
-        public static final String POSTGRESQL = "10.0";
 
         // This must be aligned on the H2 version in the Quarkus BOM
         public static final String H2 = "2.1.210";