fix tip length

Author: phaseloop

src/Mod/CAM/Tools/Bit/30degree_Vbit.fctb

@@ -7,7 +7,7 @@
     "Diameter": "10.0000 mm",
     "CuttingEdgeHeight": "1.0000 mm",
     "TipDiameter": "0.1000 mm",
-    "Length": "20.0000 mm",
+    "Length": "30.0000 mm",
     "ShankDiameter": "5.0000 mm"
   },
   "attribute": {}