feat(actions): add post-step support for composite actions

.gitea/actions/with-post-step/action.yml

@@ -0,0 +1,11 @@
+name: "with-post-step"
+description: "Runs a main command and, afterwards, a post command."
+inputs:
+  main: { description: "Command for the main step", required: true }
+  post: { description: "Command for the post step", required: true }
+  key: { description: "State key", default: POST }
+
+runs:
+  using: node20
+  main: main.js
+  post: main.js

.gitea/actions/with-post-step/main.js

@@ -0,0 +1,18 @@
+const { spawn } = require("child_process");
+const { appendFileSync } = require("fs");
+const { EOL } = require("os");
+
+function run(cmd) {
+  const proc = spawn(cmd, { stdio: "inherit", shell: true });
+  proc.on("exit", code => process.exitCode = code);
+}
+
+const key = process.env.INPUT_KEY.toUpperCase();
+if (process.env[`STATE_${key}`] !== undefined) {
+  // ---------- POST ----------
+  run(process.env.INPUT_POST);
+} else {
+  // ---------- MAIN ----------
+  appendFileSync(process.env.GITHUB_STATE, `${key}=true${EOL}`);
+  run(process.env.INPUT_MAIN);
+}