chore: updated vendored igraph to nearly-0.9.6

ntamas · ntamas · commit 8994aa6e0ea4 · 2022-01-05T08:43:01.000+01:00
diff --git a/vendor/source/igraph b/vendor/source/igraph
@@ -1 +1 @@
-Subproject commit 8bb3224ab3cfb71bacb0621412d3d43b61a5d676
+Subproject commit ee7875fd026600d8a47dbb6c456f0195e5e9a260
