Update GitHub Actions workflow for Psalm with PHP 8.4 and improved caching

Author: hkp22

.github/workflows/psalm.yml

@@ -5,26 +5,30 @@ on:
     paths:
       - '**.php'
       - 'psalm.xml.dist'
+      - 'composer.json'
+      - 'composer.lock'
+  pull_request:
+    paths:
+      - '**.php'
+      - 'psalm.xml.dist'
+      - 'composer.json'
+      - 'composer.lock'
 
 jobs:
   psalm:
     name: psalm
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '7.4'
+          php-version: '8.4'
           extensions: dom, curl, libxml, mbstring, zip, pcntl, pdo, sqlite, pdo_sqlite, bcmath, soap, intl, gd, exif, iconv, imagick
           coverage: none
-
-      - name: Cache composer dependencies
-        uses: actions/cache@v2
-        with:
-          path: vendor
-          key: composer-${{ hashFiles('composer.lock') }}
+          tools: composer:v2
+          cache: composer
 
       - name: Run composer install
         run: composer install -n --prefer-dist