rust: Pin protobuf to crate version 2.27.1 am: 6b6e0230eb

Original change: https://android-review.googlesource.com/c/trusty/app/keymint/+/2753350

Change-Id: I6d3fd4cd7fe84f110a3040dda67c36e11937acee
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/rules.mk b/rules.mk
index 4f9ac18..47e34e5 100644
--- a/rules.mk
+++ b/rules.mk
@@ -33,7 +33,7 @@
 	trusty/user/base/lib/keymint-rust/common \
 	trusty/user/base/lib/keymint-rust/ta \
 	$(call FIND_CRATE,log) \
-	$(call FIND_CRATE,protobuf) \
+	$(call FIND_CRATE,protobuf)/2.27.1 \
 	trusty/user/base/lib/storage/rust \
 	trusty/user/base/lib/tipc/rust \
 	trusty/user/base/lib/system_state/rust \