fix: respect semantic config if it exists

Fixes #199

README.md

@@ -199,7 +199,7 @@ You can pass in `semantic-release` configuration options via GitHub Action input
 It's important to note, **NONE** of these inputs are required. Semantic release has a default
 configuration that it will use if you don't provide any.
 
-Also of note, if you'd like to override the default configuration and you'd rather not use the
+Also of note, if you'd like to override the default configuration, and you'd rather not use the
 inputs here, the action will automatically use any
 [`semantic-release` configuration](https://github.com/semantic-release/semantic-release/blob/master/docs/usage/configuration.md#configuration-file)
 defined in your repo (`.releaserc`, `release.config.js`, `release` prop in `package.json`)

entrypoint.js

@@ -3,6 +3,7 @@ import core from '@actions/core';
 import semanticRelease from 'semantic-release';
 import JSON5 from 'json5';
 import arrify from 'arrify';
+import { cosmiconfig } from 'cosmiconfig';
 
 const parseInput = (input, defaultValue = '') => {
   try {
@@ -73,17 +74,27 @@ const setGitConfigSafeDirectory = () => {
  * @see https://github.com/semantic-release/semantic-release/blob/master/docs/usage/configuration.md#options
  */
 async function run() {
+  const configFile = await cosmiconfig('release')
+    .search()
+    .then((result) => result?.config);
   const branch = parseInput(core.getInput('branch', { required: false }));
-  const branches = parseInput(core.getInput('branches', { required: false }), [
-    'master',
-    'main',
-    'next',
-    'next-major',
-    '+([0-9])?(.{+([0-9]),x}).x',
-    { name: 'beta', prerelease: true },
-    { name: 'alpha', prerelease: true },
-    { name: 'canary', prerelease: true },
-  ]);
+  // Branches are parsed in this order:
+  // 1. Input from the action
+  // 2. Config file
+  // 3. Default branches set in this action = semantic-release's default branches with the addition of `main`.
+  const branches = parseInput(
+    core.getInput('branches', { required: false }),
+    configFile?.branches || [
+      'master',
+      'main',
+      'next',
+      'next-major',
+      '+([0-9])?(.{+([0-9]),x}).x',
+      { name: 'beta', prerelease: true },
+      { name: 'alpha', prerelease: true },
+      { name: 'canary', prerelease: true },
+    ],
+  );
   const plugins = parseInput(core.getInput('plugins', { required: false }));
   const additionalPackages =
     parseInput(core.getInput('additional-packages', { required: false })) || [];

package.json

@@ -17,6 +17,7 @@
     "@actions/core": "^1.10.1",
     "@babel/runtime": "^7.23.2",
     "arrify": "^3.0.0",
+    "cosmiconfig": "^9.0.0",
     "json5": "^2.2.1",
     "semantic-release": "^22.0.5"
   },