feat(tractor): update water level and add replenish functionality

src/tractor.py

@@ -16,7 +16,8 @@ class Tractor(pygame.sprite.Sprite):
         x, y = 0, 0
         self.rect.topleft = (x, y)
 
-        self.water = 200
+        self.water = 50
+
 
     def draw(self, surface):
         surface.blit(self.image, self.rect)
@@ -54,6 +55,9 @@ class Tractor(pygame.sprite.Sprite):
             self.move('up')
         if keys[pygame.K_DOWN]:
             self.move('down')
+        if keys[pygame.K_r]:
+            self.water = 50
+            print(f"💧 replenished water level: {self.water} litres\n")
 
 
     def print_tile_type(self):