Update KiCad domain.

https://www.kicad.org/blog/2021/10/Avoid-links-to-former-kicad-domain/

KiCad.gitignore

@@ -1,5 +1,5 @@
-# For PCBs designed using KiCad: http://www.kicad-pcb.org/
-# Format documentation: http://kicad-pcb.org/help/file-formats/
+# For PCBs designed using KiCad: https://www.kicad.org/
+# Format documentation: https://kicad.org/help/file-formats/
 
 # Temporary files
 *.000