message: doc: add explicit example with ^ and leading 0
  Since the leading 0 is treated a bit special, its worth it to have an
  explicit example to match the above example of the major version being >
  0.
diff: @@ -42,6 +42,7 @@ be allowed with them:
  ^1.2 := >=1.2.0 <2.0.0
  ^1 := >=1.0.0 <2.0.0
  ^0.2.3 := >=0.2.3 <0.3.0
  +^0.2 := >= 0.2.0 < 0.3.0
  ^0.0.3 := >=0.0.3 <0.0.4
  ^0.0 := >=0.0.0 <0.1.0
  ^0 := >=0.0.0 <1.0.0
  