Add Apache Arrow sprint

Author: rok

src/content/sprints/apache_arrow.md

@@ -0,0 +1,15 @@
+---
+title: "Apache Arrow"
+numberOfPeople: "TBA"
+pythonLevel: "Intermediate"
+contactPerson:
+  name: "Rok Mihevc"
+  email: "rok.mihevc [at] gmail.com"
+links:
+  - title: "Apache Arrow"
+    url: "https://github.com/apache/arrow"
+  - title: "Proposed donation of pyarrow-stubs"
+    url: "https://github.com/apache/arrow/discussions/45919"
+---
+
+We want to add type annotations to the PyArrow project. We will sprint to identify best approach to do so by prototyping. Suggestions and discussion also welcome.