Add invoice for @wooorm

Closes GH-55.

Reviewed-by: Merlijn Vos <merlijn@soverin.net>
Reviewed-by: Christian Murphy <christian.murphy.42@gmail.com>

invoices/2022-04-30-wooorm.md

@@ -0,0 +1,18 @@
+# Invoice: unified collective
+
+*   **Date**: 2022-04-30
+*   **Person**: Titus Wormer ([**@wooorm**](https://github.com/wooorm))
+
+## Items
+
+| Item               | Description                     | Total         |
+| ------------------ | ------------------------------- | ------------- |
+| unified collective | Development and support (April) | **$4,600.00** |
+
+***
+
+These numbers are since the previous invoice, which was on 2022-03-31.
+
+*   **Commits**: [241](https://github.com/search?q=author%3Awooorm+committer-date%3A%222022-03-31..2022-04-30%22)
+*   **Issues and PRs**: [14](https://github.com/search?q=author%3Awooorm+created%3A%222022-03-31..2022-04-30%22)
+*   **Reviews**: [30](https://github.com/search?q=reviewed-by%3Awooorm+created%3A%222022-03-31..2022-04-30%22)