[roll] Roll fuchsia [archivist] Optimize some immutable strings

When no mutability of a String is desired, using Box<str> is slightly
more efficient (8 bytes less). Since in addition to pointer and length,
String also stores capacity.

Tested: existing tests

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/582779
Original-Revision: de622974d2bac3df4fd74fc9bfcbffc3364f8762
GitOrigin-RevId: d5673bc8a68075288f6697423557cc86bfad345f
Change-Id: Ia1cfc13bd2a200c50e06787484a4fa854e3229bf
diff --git a/stem b/stem
index 1977ca9..4e89753 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="fc54e52f72ab87e6656548aee0a5c6f7c7b40a15"/>
+             revision="de622974d2bac3df4fd74fc9bfcbffc3364f8762"/>
   </projects>
   <hooks>
     <hook name="install-environment"