Add invoice for @wooorm

Closes GH-49.

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

invoices/2021-10-31-wooorm.md

@@ -0,0 +1,19 @@
+# Invoice: unified collective
+
+*   **Date**: 2021-10-31
+*   **Person**: Titus Wormer ([**@wooorm**](https://github.com/wooorm))
+
+## Items
+
+| Item               | Description                       | Total         |
+| ------------------ | --------------------------------- | ------------- |
+| unified collective | Development and support (October) | **$4,600.00** |
+
+***
+
+These numbers are since the previous invoice, which was on 2021-09-30.
+
+*   **Commits**:
+    [458](https://github.com/search?q=author%3Awooorm+committer-date%3A%222021-09-30..2021-10-31%22)
+*   **Issues and PRs**: [68](https://github.com/search?q=author%3Awooorm+created%3A%222021-09-30..2021-10-31%22)
+*   **Reviews**: [46](https://github.com/search?q=reviewed-by%3Awooorm+created%3A%222021-09-30..2021-10-31%22)