Try pinning pillow to fix ci (mwaskom#3727)

mwaskom · web-flow · commit 2f5ea60930b9 · 2024-07-11T07:23:32.000-04:00
diff --git a/ci/deps_pinned.txt b/ci/deps_pinned.txt
@@ -3,3 +3,4 @@ pandas~=1.2.0
 matplotlib~=3.4.0
 scipy~=1.7.0
 statsmodels~=0.12.0
+pillow~=10.3.0
