Add a 'default' clause to this 'switch' statement.

[Paulo Duarte]

Codacy detected an issue:

Message: Add a 'default' clause to this 'switch' statement.

Occurred on:

• Commit: 6e3a35c
• File: Gadz.Tetris.Core/Model/Stats.cs
• LineNum: 146
• Code: switch (linhas)

Currently on:

• Commit: 3bdd4ce
• File: Gadz.Tetris.Core/Model/Stats.cs
• LineNum: 146