add link to help-wanted label filter (#74)

.github/ISSUE_TEMPLATE/improvement.yml

@@ -25,3 +25,10 @@ body:
     attributes:
       label: Benefits
       description: Highlight the advantages and benefits of implementing this improvement 
+
+  - type: checkboxes
+    attributes:
+      label: Do you want to contribute to this issue?
+      description: If you want, you will be assigned to the issue and can make a pull request fixing it.
+      Otherwise, a `help-wanted` label will be added to it. The first contributor who asks to
+      contribute will be assigned the issue and the `help-wanted` label will be removed

CONTRIBUTING.md

@@ -21,6 +21,12 @@ A UI example is simply an HTML file containing DaisyUI, TailwindCSS and Font Awe
 
 ## Contributing
 
+## Issues to contribute
+
+If you want to contribute to issues that are not assigned to anyone else, use
+[this issue filter](https://github.com/willpinha/daisy-collection/issues?q=is%3Aopen+is%3Aissue+label%3Ahelp-wanted)
+to select all issues with the `help-wanted` label
+
 ### Add a new UI example
 
 #### 1. Fork the repository