Update autoload path resolution (#189)

This change uses various possible path locations to locate the `autoload.php` file and throws an error if not found.
It closes #188

.github/workflows/main.yml

@@ -178,6 +178,16 @@ jobs:
         run: |
           ! $BLUEPRINT $CMD_VALIDATE $INVALID_TEST
 
+      - name: Test as composer package
+        run: |
+          mkdir -pv ./build/composer-test
+          cd ./build/composer-test
+          composer init --no-interaction --name="test/test"
+          composer require jbzoo/csv-blueprint
+          ./vendor/bin/csv-blueprint || true
+          ./vendor/bin/csv-blueprint $CMD_VALIDATE $VALID_TEST || true
+          ./vendor/bin/csv-blueprint $CMD_VALIDATE $INVALID_TEST || true
+
 
   verify-phar-binary:
     name: Verify Phar

csv-blueprint.php

@@ -17,7 +17,25 @@
 namespace JBZoo\CsvBlueprint;
 
 \define('PATH_ROOT', __DIR__);
-require_once PATH_ROOT . '/vendor/autoload.php';
+
+foreach (
+    [
+        PATH_ROOT . '/../../autoload.php',
+        PATH_ROOT . '/../vendor/autoload.php',
+        PATH_ROOT . '/vendor/autoload.php',
+    ] as $file
+) {
+    if (\file_exists($file)) {
+        \define('JBZOO_AUTOLOAD_FILE', $file);
+        break;
+    }
+}
+
+if (\defined('JBZOO_AUTOLOAD_FILE')) {
+    require_once JBZOO_AUTOLOAD_FILE;
+} else {
+    throw new Exception('Cannot find composer autoload file');
+}
 
 if ('cli' !== \PHP_SAPI) {
     throw new Exception('This script must be run from the command line.');