Log Message:
update devel/jsonnet to version 0.13.0

Significant changes since last packaged version (0.10.0):
- jsonnet fmt is now its own executable called jsonnetfmt...
- Standard library additions: std.reverse, std.encodeUTF8 and std.decodeUTF8
- Standard dlibrary changes:
  - Fix std.parseHex that rejected certain correct inputs
  - Added std.find and std.findSubstr
  - Added std.parseJson
  - sort and set functions can now be given a "keyF" function for \ 
controlling the ordering
  - std.trace for debugging
  - std.parseHex and std.parseOctal
- Language changes:
  - std.native("foo") now returns null if foo doesn't exist, instead \ 
of an error...

Complete list of change is available from https://github.com/google/jsonnet/releases