While running the tk apply command with multiple --tla-code arguments, each containing a key='value' parameter, I noticed that the JSONNET code would not receive them correctly. More specifically, instead of being passed as named parameters, they are passed as positional parameters and since they're stored in a jsonnet.InjectedCode map, they end up being serialised in an arbitrary order which differs each time Tanka is run. I added a test in this PR which highlights this issue (you might need to run it multiple times to get a failure).

Note that this issue only surfaces when using multiple --tla-code args when calling tk apply.

I am rather new to this tool, so I'm not fully aware of all the ways in which people use the --tla-code argument. Please let me know if I missed any other edge cases.