fix mkdocstrings python dependency
diff --git a/setup.cfg b/setup.cfg
index d64419e..5297c9c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -64,4 +64,4 @@
 documentation =
     mkdocs >= 1.2.3
     mkdocs-material >= 8.1.9
-    mkdocstrings >= 0.17.0
+    mkdocstrings[python] >= 0.19.0