Add Psalm to GitHub Actions

.github/workflows/static-analysis.yml

@@ -0,0 +1,31 @@
+---
+name: Static analysis
+
+on:
+  pull_request:
+  push:
+    paths:
+      - '**.php'
+      - '*psalm.xml'
+
+jobs:
+  psalm:
+    name: Psalm
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v1
+        with:
+          php-version: 7.4
+          coverage: none
+
+      - name: Cache Composer dependencies
+        uses: actions/cache@v1
+        with:
+          path: vendor
+          key: composer-${{ hashFiles('composer.lock' )}}
+
+      - name: Run Psalm
+        run: make static-code-analysis

Makefile

@@ -1,6 +1,6 @@
 .PHONY: *
 
-static-code-analysis:
+static-code-analysis: vendor
 	php vendor/bin/psalm --show-info=true
 
 phpcs:
@@ -10,3 +10,7 @@ phpunit:
 	php vendor/bin/phpunit -v --color=always --testdox tests
 
 test: phpunit phpcs
+
+vendor: composer.json
+	composer validate --strict
+	composer install

composer.json

@@ -1,5 +1,6 @@
 {
     "name": "opdavies/glassboxx-sdk-php",
+    "description": "A PHP SDK for creating customers and orders in Glassboxx.",
     "type": "library",
     "license": "MIT",
     "authors": [