opencollective badge added

index.html

@@ -1155,6 +1155,10 @@ <h1 id="support">Show your support</h1>
 <h2>Star <a href="https://github.com/sepandhaghighi/art">this</a> repo</h2>
 <p>Give a ⭐️ if this project helped you!</p>
 <h2>Donate to our project</h2>
+<h3>Open Collective</h3>
+<a href="https://opencollective.com/openscilab/projects/artoc" target="_blank">
+  <img src="https://opencollective.com/webpack/donate/[email protected]?color=blue" width=300>
+</a>
 <h3>Buy me a coffee</h3>
 <a href="https://www.buymeacoffee.com/asciiart"><img src="https://img.buymeacoffee.com/button-api/?text=Buy me a coffee&emoji=&slug=asciiart&button_colour=FFDD00&font_colour=000000&font_family=Cookie&outline_colour=000000&coffee_colour=ffffff" /></a>  
 <h3>Coffeete</h3>