fix dbal deprecation

app/src/Lib/Util/SchemaManager.php

@@ -62,6 +62,9 @@ class SchemaManager {
   // The column library from the main config
   protected $columnLibrary = null;
 
+  // The current platform
+  protected $platform = null;
+
   /**
    * Construct a new SchemaManager.
    * 
@@ -98,6 +101,7 @@ public function __construct(?ConsoleIo $io=null, string $connection='default') {
 
     $this->conn = DriverManager::getConnection($cfargs, $config);
     $this->driver = $cfg['driver'];
+    $this->platform = $this->conn->getDatabasePlatform();
   }
 
   /**
@@ -358,8 +362,7 @@ protected function processSchema(
       // schema file).
       $comparator = new Comparator();
       $schemaDiff = $comparator->compareSchemas($curSchema, $schema);
-
-      $diffSql = $schemaDiff->toSaveSql($this->conn->getDatabasePlatform());
+      $diffSql = $this->platform->getAlterSchemaSQL($schemaDiff);
 
       // We don't start a transaction since in general we always want to move to
       // the desired state, and if we fail in flight it's probably a bug that