Implement the "publish-action" action

src/main.ts

@@ -0,0 +1,26 @@
+import * as core from '@actions/core';
+import * as github from '@actions/github';
+import { updateTag, validateIfReleaseIsPublished } from './api-utils';
+import { validateSemverVersionFromTag, getMajorTagFromFullTag } from './version-utils';
+
+async function run(): Promise<void> {
+    try {
+        const token = core.getInput('token');
+        const octokitClient = github.getOctokit(token);
+        const sourceTagName = core.getInput('source-tag');
+
+        validateSemverVersionFromTag(sourceTagName);
+
+        await validateIfReleaseIsPublished(sourceTagName, octokitClient);
+
+        const majorTag = getMajorTagFromFullTag(sourceTagName);
+        await updateTag(sourceTagName, majorTag, octokitClient);
+
+        core.setOutput('major-tag', majorTag);
+        core.info(`The '${majorTag}' major tag now points to the '${sourceTagName}' tag`);
+    } catch (error) {
+        core.setFailed(error.message);
+    }
+};
+
+run();