Add advisory for bigint

Author: elichai

crates/bigint/RUSTSEC-0000-0000.toml

@@ -0,0 +1,20 @@
+[advisory]
+id = "RUSTSEC-0000-0000"
+
+package = "bigint"
+
+date = "2020-05-07"
+
+title = "Undefined Behavior"
+
+categories = ["memory-corruption"]
+
+keywords = ["ub", "undefined", "uninit"]
+
+description = """
+Affected versions of this crate contained multiple Undefined Behaviours
+Triggering Undefined Behavior can produce unknown results and thus isn't safe to use
+"""
+
+[versions]
+patched = []