allow pnpm to be used as package manager

.gitignore

@@ -14,3 +14,5 @@ typings/
 
 # Optional eslint cache
 .eslintcache
+
+.vscode

README.md

@@ -76,6 +76,9 @@ configuration options:
   Provided as an [input][github-action-input].
   Defaults to `{actor}@users.noreply.github.com`, where `{actor}` is the GitHub username 
   of the action actor.
+
+- **pkg-manager**: Provide a custom package manager other than npm.
+  Provided as an [input][github-action-input].
 
 ### Org or User Pages
 

action.yml

@@ -39,6 +39,10 @@ inputs:
     description: "The email adress under which the deploy commit is pushed to the deploy branch."
     required: false
     default: ""
+  pkg-manager:
+    description: "The package manager used to manage the project"
+    required: false
+    default: ""
 runs:
   using: "node12"
   main: "./dist/index.js"

index.ts

@@ -6,6 +6,12 @@ import * as ioUtil from '@actions/io/lib/io-util'
 
 const DEFAULT_DEPLOY_BRANCH = 'master'
 
+async function getPkgManager(workingDir: string) {
+  if (await ioUtil.exists(`${workingDir}/pnpm-lock.yaml`)) return 'pnpm'
+  if (await ioUtil.exists(`${workingDir}/yarn.lock`)) return 'yarn'
+  return 'npm'
+}
+
 async function run(): Promise<void> {
   try {
     const skipPublish = (core.getInput('skip-publish') || 'false').toUpperCase()
@@ -31,7 +37,7 @@ async function run(): Promise<void> {
     }
 
     const workingDir = core.getInput('working-dir') || '.'
-    const pkgManager = (await ioUtil.exists(`${workingDir}/yarn.lock`)) ? 'yarn' : 'npm'
+    const pkgManager = core.getInput('pkg-manager') || (await getPkgManager(workingDir))
     console.log(`Installing your site's dependencies using ${pkgManager}.`)
     await exec.exec(`${pkgManager} install`, [], {cwd: workingDir})
     console.log('Finished installing dependencies.')
@@ -49,7 +55,9 @@ async function run(): Promise<void> {
     const cnameExists = await ioUtil.exists(`${workingDir}/CNAME`)
     if (cnameExists) {
       console.log('Copying CNAME over.')
-      await io.cp(`${workingDir}/CNAME`, `${workingDir}/public/CNAME`, {force: true})
+      await io.cp(`${workingDir}/CNAME`, `${workingDir}/public/CNAME`, {
+        force: true,
+      })
       console.log('Finished copying CNAME.')
     }
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gatsby-gh-pages-action",
-  "version": "2.1.1",
+  "version": "2.2.1",
   "description": "GitHub Action to build and deploy your Gatsby site to GitHub Pages ❤️🎩",
   "main": "dist/index.js",
   "scripts": {