Incorrect resolve on key on

[lonegunmanb]

I've tried to decode github action yaml file:

name: build

on:
  push:
    branches:
      - main
  pull_request:

func TestFunction_YamlDecode(t *testing.T) {
	code := `yamldecode("name: build\n\non:\n  push:\n    branches:\n        - main\n    pull_request:\n")`
	exp, diag := hclsyntax.ParseExpression([]byte(code), "test.hcl", hcl.InitialPos)
	require.False(t, diag.HasErrors())
	value, diag := exp.Value(&hcl.EvalContext{Functions: Functions(".")})
	require.False(t, diag.HasErrors())
	valueMap := value.AsValueMap()
	assert.Contains(t, valueMap, "on")
}

The key on has been resolved as true.

I found this issue was caused by the following function in resolve.go:

func (c *Converter) resolveScalar(tag string, src string, style yaml_scalar_style_t) (cty.Value, error) {
	if !resolvableTag(tag) {
		return cty.NilVal, fmt.Errorf("unsupported tag %q", tag)
	}

	// Any data is accepted as a !!str or !!binary.
	// Otherwise, the prefix is enough of a hint about what it might be.
	hint := byte('N')
	if src != "" {
		hint = resolveTable[src[0]]
	}
	if hint != 0 && tag != yaml_STR_TAG && tag != yaml_BINARY_TAG {
		if style == yaml_SINGLE_QUOTED_SCALAR_STYLE || style == yaml_DOUBLE_QUOTED_SCALAR_STYLE {
			return cty.StringVal(src), nil
		}

		// Handle things we can lookup in a map.
>		if item, ok := resolveMap[src]; ok {
			return item.value, nil
		}

I understand that we use this resolveMap to convert on or On to true, but I don't think we should convert yaml keys.