Fix docstring indent issue in feature files

features/package-install.feature

@@ -22,21 +22,21 @@ Feature: Install WP-CLI packages
       }
       """
     And a dummy-package/composer.json file:
-	  """
-	  {
-	    "name": "wp-cli/restful",
-	    "description": "This is a dummy package we will install instead of actually installing the real package. This prevents the test from hanging indefinitely for some reason, even though it passes. The 'name' must match a real package as it is checked against the package index."
-	  }
-	  """
+      """
+      {
+        "name": "wp-cli/restful",
+        "description": "This is a dummy package we will install instead of actually installing the real package. This prevents the test from hanging indefinitely for some reason, even though it passes. The 'name' must match a real package as it is checked against the package index."
+      }
+      """
     When I run `WP_CLI_PACKAGES_DIR=. wp package install wp-cli/restful`
     Then STDOUT should contain:
-	  """
-	  Updating package index repository url...
-	  """
+      """
+      Updating package index repository url...
+      """
     And STDOUT should contain:
-	  """
-	  Success: Package installed
-	  """
+      """
+      Success: Package installed
+      """
     And the composer.json file should contain:
       """
       "url": "https://wp-cli.org/package-index/"