Upgrade rust/crates/regex to 1.4.3

Test: make
Change-Id: I0a2f64e0e7e81dc3e46c5c21ffa0bfbc7b1fb28f
diff --git a/METADATA b/METADATA
index 663a944..1e7c0d3 100644
--- a/METADATA
+++ b/METADATA
@@ -7,13 +7,13 @@
   }
   url {
     type: ARCHIVE
-    value: "https://static.crates.io/crates/regex/regex-1.4.2.crate"
+    value: "https://static.crates.io/crates/regex/regex-1.4.3.crate"
   }
-  version: "1.4.2"
+  version: "1.4.3"
   license_type: NOTICE
   last_upgrade_date {
-    year: 2020
-    month: 11
-    day: 2
+    year: 2021
+    month: 1
+    day: 8
   }
 }