support fly config in json and yaml formats

[rubys]

fly launch using the configuration of your choice -- toml remains the default, but --json or --yaml can be specified to select an alternate format.

Or convert at any time using fly config show --local and specify --yaml or --toml and redirect the output to a file with the correct file extension. (json remains the default for this command). Just remember to delete the other representation -- the search order is fly.toml, then fly.json, then fly.yaml.

fly config save can also be used (it defaults to toml).

[dangra]

Come to say I love the work you are doing here, adding json and yaml support is awesome but please add unit tests. TOML is well tested now, not perfect but covers many legacy stuff that we don't want to break. I'd like to see a similar level of test coverage for yaml and json.

[rubys]

@dangra If you look in testdata, you will now see full-reference in all three formats. There were produced using bin/flyctl config show --local. And there now are tests that loading these configurations produce identical configurations as the original toml file.

This demonstrates that configurations can round-trip in all three formats.

Any other suggestions?

[dangra]

💯

[dangra]