Update safemem to 0.3

LunaBorowska · LunaBorowska · commit 80fc25648602 · 2019-07-31T10:58:48.000+02:00
safemem 0.3.1 fixes undefined behaviour in it.
diff --git a/Cargo.toml b/Cargo.toml
@@ -16,7 +16,7 @@ license = "MIT OR Apache-2.0"
 readme = "README.md"
 
 [dependencies]
-safemem = "0.2"
+safemem = "0.3"
 memchr = "2.0"
 
 # `slice_deque` is only supported on platforms with virtual memory
