Add tag_name option (#39)

Allow setting tag name like actions/create-release.

src/main.ts

@@ -7,7 +7,7 @@ import { env } from "process";
 async function run() {
   try {
     const config = parseConfig(env);
-    if (!isTag(config.github_ref)) {
+    if (!config.input_tag_name && !isTag(config.github_ref)) {
       throw new Error(`⚠️ GitHub Releases requires a tag`);
     }
     GitHub.plugin(require("@octokit/plugin-throttling"));