fix: Compare correctly for warning status

mapfile/template.j2

@@ -140,14 +140,14 @@ LAYER
   
     CLASS
       NAME "Low infection risk"
-      EXPRESSION ([pixel] >= 0 AND [pixel] < 15) 
+      EXPRESSION ([pixel] >= 0 AND [pixel] < 3) 
       STYLE
           COLOR 58 196 125 # Green
       END
     END
     CLASS
       NAME "High infection risk"
-      EXPRESSION ([pixel] >= 15) 
+      EXPRESSION ([pixel] >= 3) 
       STYLE
           COLOR 217 37 80 # Red
       END