chore: updated vendored igraph to 0.9.6

ntamas · ntamas · commit dd8390b3d8eb · 2022-01-06T08:37:40.000+01:00
diff --git a/vendor/source/igraph b/vendor/source/igraph
@@ -1 +1 @@
-Subproject commit ee7875fd026600d8a47dbb6c456f0195e5e9a260
+Subproject commit 2fe8640888d19c146e4c8970478a3485a3e485e3
