Open Collective: update img shields

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -92,10 +92,10 @@ This project exists thanks to all the people who contribute.
 
 <p align="left">
   <a href="https://opencollective.com/the-book-of-secret-knowledge" alt="Financial Contributors on Open Collective">
-    <img src="https://img.shields.io/opencollective/backers/the-book-of-secret-knowledge?style=for-the-badge&color=FF4500&labelColor=111111"></a>
+    <img src="https://img.shields.io/opencollective/backers/the-book-of-secret-knowledge?style=for-the-badge&color=FF4500&labelColor=A9A9A9"></a>
   </a>
   <a href="https://opencollective.com/the-book-of-secret-knowledge" alt="Financial Contributors on Open Collective">
-    <img src="https://img.shields.io/opencollective/sponsors/the-book-of-secret-knowledge?style=for-the-badge&color=FF4500&labelColor=111111"></a>
+    <img src="https://img.shields.io/opencollective/sponsors/the-book-of-secret-knowledge?style=for-the-badge&color=FF4500&labelColor=A9A9A9"></a>
   </a>
 </p>