fix: EXPOSED-707 Handle MariaDB fractional seconds support since vers…

…ion 5.3

According to the documentation [here](https://mariadb.com/kb/en/changes-improvements-in-mariadb-5-3/#datatypes), MariaDB introduced fractional seconds support in temporal data types from version 5.3. For MySQL, it's from version 5.6. Previously, Exposed was assuming it was 5.6 for both MariaDB and MySQL.

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Database.kt

@@ -72,7 +72,7 @@ class Database private constructor(
 
     /** Whether the version number of the database is equal to or greater than the provided [majorVersion] and [minorVersion]. */
     fun isVersionCovers(majorVersion: Int, minorVersion: Int) =
-        this.majorVersion >= majorVersion && this.minorVersion >= minorVersion
+        this.majorVersion > majorVersion || (this.majorVersion == majorVersion && this.minorVersion >= minorVersion)
 
     /** Whether the database supports ALTER TABLE with an add column clause. */
     val supportsAlterTableWithAddColumn by lazy(

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/MysqlDialect.kt

@@ -356,10 +356,14 @@ open class MysqlDialect : VendorDialect(dialectName, MysqlDataTypeProvider, Mysq
 
     override val supportsSetDefaultReferenceOption: Boolean = false
 
-    /** Returns `true` if the MySQL JDBC connector version is greater than or equal to 5.6. */
-    fun isFractionDateTimeSupported(): Boolean = TransactionManager.current().db.isVersionCovers(BigDecimal("5.6"))
-
-    /** Returns `true` if a MySQL JDBC connector is being used and its version is greater than or equal to 8.0. */
+    /** Returns `true` if the database version is greater than or equal to 5.6 for MySQL, or 5.3 for MariaDB. */
+    @Suppress("MagicNumber")
+    fun isFractionDateTimeSupported(): Boolean = TransactionManager.current().db.isVersionCovers(
+        5,
+        if (currentDialect is MariaDBDialect) 3 else 6
+    )
+
+    /** Returns `true` if a MySQL database is being used and its version is greater than or equal to 8.0. */
     fun isTimeZoneOffsetSupported(): Boolean = (currentDialect !is MariaDBDialect) && isMysql8
 
     private val notAcceptableDefaults = mutableListOf("CURRENT_DATE()", "CURRENT_DATE")