Update dependencies and use Node 20 - #425

Hello from actions/github-script! (ba396f6)

Looks like there's a legitimate failure with the preview integration test:

- Validating previews set to a single value
Error: ❌ Expected 'application/vnd.github.foo-preview+json', got application/vnd.github.v3+json
Error: Process completed with exit code 1.

You could probably also update to the node20 versions of related actions:

• actions/checkout@v4
• actions/setup-node@v4

Looks like there's a legitimate failure with the preview integration test:

Previews are no longer supported in Octokit unless you are sending a request to /graphql: octokit/endpoint.js@376276d. This aligns with how previews have been phased out from the GitHub REST API (https://github.blog/changelog/2021-10-14-rest-api-preview-promotions) and the documentation was removed a couple years ago.

So probably worth adjusting the test to be a GraphQL one and adjusting any needed documentation accordingly.

Took a look at the failing test and I think I figured it out. Seems like the problem lies with the updated @actions/Github and octokit dependencies.

Looking at this code segment that deals with the previews - which has been pulled in with the dependency updates. It only applies previews if the route is /graphql.

Some local testing:

INPUT_SCRIPT="return github.request.endpoint({url: \"/graphql\"}).headers.accept" INPUT_GITHUB_TOKEN=<redacted> INPUT_RESULT_ENCODING=string INPUT_PREVIEWS=foo INPUT_DEBUG=true INPUT_RETRIES=0 node ./dist/index.js

::set-output name=result::application/vnd.github.foo-preview+json

And without {url: \"/graphql\"} (as in the workflow file):

INPUT_SCRIPT="return github.request.endpoint({}).headers.accept" INPUT_GITHUB_TOKEN=<redacted> INPUT_RESULT_ENCODING=string INPUT_PREVIEWS=foo INPUT_DEBUG=true INPUT_RETRIES=0 node ./dist/index.js

::set-output name=result::application/vnd.github.v3+json

I'm able to run that ^ because I've made changes to main.ts which switches necessary input names from kebab-case to snake_case because my shell (and most shells) don't support - in environment variable names.

diff --git a/src/main.ts b/src/main.ts
index 44b1270..6e82709 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -23,7 +23,7 @@ type Options = {
 }
 
 async function main(): Promise<void> {
-  const token = core.getInput('github-token', {required: true})
+  const token = core.getInput('github_token', {required: true})
   const debug = core.getBooleanInput('debug')
   const userAgent = core.getInput('user-agent')
   const previews = core.getInput('previews')
@@ -63,7 +63,7 @@ async function main(): Promise<void> {
     script
   )
 
-  let encoding = core.getInput('result-encoding')
+  let encoding = core.getInput('result_encoding')
   encoding = encoding ? encoding : 'json'
 
   let output