JSON error

when running with documented config:

```
lgwapnitsky@blog:~/lgw_11ty$ eleventy-social-images --site-name "Larry G. Wapnitsky"
Starting social images...
(node:18860) UnhandledPromiseRejectionWarning: SyntaxError: /home/lgwapnitsky/lgw_11ty/pages.json: Unexpected number in JSON at position 1
at parse ()
at Object.Module._extensions..json (internal/modules/cjs/loader.js:1106:22)
at Module.load (internal/modules/cjs/loader.js:928:32)
at Function.Module._load (internal/modules/cjs/loader.js:769:14)
at Module.require (internal/modules/cjs/loader.js:952:19)
at require (internal/modules/cjs/helpers.js:88:18)
at /home/lgwapnitsky/lgw_11ty/node_modules/@11tyrocks/eleventy-plugin-social-images/bin/social-images.js:82:17
at processTicksAndRejections (internal/process/task_queues.js:93:5)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:18860) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:18860) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

```

pages.json file:

```
---
permalink: ./pages.json
permalinkBypassOutputDir: true
eleventyExcludeFromCollections: true
---
[
{%- for pages in collections.all %}
{
"title":"{{ pages.data.title | addNbsp | safe }}",
"imgName":"{{ pages.data.title | slug }}"
}{% if loop.last == false %},{% endif -%}
{% endfor %}
]
```

The error occurs in bin/social-images.js at line 82 when trying to parse pages.json. First, examine the JSON generation in the Eleventy template to ensure it outputs valid JSON. Then, check the parsing logic in the plugin to see if it handles the file correctly. Running the command with the provided config and inspecting the generated pages.json file will help identify the syntax issue.

索引モデルが issue の本文から書いたものです。