Revert "update backtrace-rs"

Mark-Simulacrum · Mark-Simulacrum · commit 744240678371 · 2020-07-22T07:16:45.000-04:00
This reverts commit 4cbd265.
diff --git a/src/backtrace b/src/backtrace
@@ -1 +1 @@
-Subproject commit 5965cf5fc17affc84c11dc9972ae8f4dc2c32db1
+Subproject commit 8f89434446f72f27f8145d8bbc1a302c6ef29d1e
