Native user_version support in Connection

Author: nathanfallet

Sources/SQLite/Core/Connection.swift

@@ -151,6 +151,13 @@ public final class Connection {
     public var totalChanges: Int {
         Int(sqlite3_total_changes(handle))
     }
+    
+    /// The user version of the database.
+    /// See SQLite [PRAGMA user_version](https://sqlite.org/pragma.html#pragma_user_version)
+    public var userVersion: Int32 {
+        get { return Int32(try! scalar("PRAGMA user_version") as! Int64)}
+        set { try! run("PRAGMA user_version = \(newValue)") }
+    }
 
     // MARK: - Execute