Add some extra fields to the iBoM.

Some capacitors have the same value (e.g. 100nF) but different voltage
ratings. In some cases you fit the same parts, and in some cases you
fit different parts (depends on availability!)

Author: thejpster

Kicad/docs.kibot.yaml

@@ -217,6 +217,7 @@ outputs:
     type: ibom
     options:
       output: '%f-ibom-%r.%x'
+      extra_fields: "Voltage,Tolerance,Manufacturer,MPN"
 
   - name: 'make_jlc_position'
     comment: "Generate pick and place file, JLC style"