[Core feature request] Access workflow inputs in Kotlin-based step

[krzema12]

What feature do you need?
https://docs.github.com/en/enterprise-cloud@latest/actions/writing-workflows/choosing-what-your-workflow-does/accessing-contextual-information-about-workflow-runs#inputs-context

The access could be even type-unsafe for now (just strings).

Do you have an example usage?

run {
    println(inputs["myInput"])
}

Is there a workaround for not having this feature? If yes, please describe it.

I'm currently doing something pretty ugly:

            val githubContextJson = System.getenv("GHWKT_GITHUB_CONTEXT_JSON")!!
            val version: String = Json.parseToJsonElement(githubContextJson)
                .jsonObject["event"]
                ?.jsonObject?.get("inputs")
                ?.jsonObject?.get("version")
                ?.jsonPrimitive?.contentOrNull
                ?: error("Version couldn't be extracted from input")

[krzema12]

Add tests for deserializing GitHub context:

github-workflows-kt/github-workflows-kt/src/main/kotlin/io/github/typesafegithub/workflows/yaml/ToYaml.kt

Line 69 in 1924c49

private fun loadContextsFromEnvVars(getenv: (String) -> String?): Contexts {