Adding new GSI public keys

Adding two new public keys for R-Developer-GSI and S-Developer-GSI,
respectively.

Bug: 149805495
Test: build then checks $OUT/recovery/root/first_stage_ramdisk/avb/.
Change-Id: I69dd00dbb0046c681758068b8bbea0c08b9e2c91
Merged-In: I69dd00dbb0046c681758068b8bbea0c08b9e2c91
(cherry picked from commit 3c739746b3ec63661b736bd47d3889fe4f29fe54)
diff --git a/target/product/developer_gsi_keys.mk b/target/product/developer_gsi_keys.mk
index 79451ad..a7e3d62 100644
--- a/target/product/developer_gsi_keys.mk
+++ b/target/product/developer_gsi_keys.mk
@@ -27,3 +27,5 @@
 #
 PRODUCT_PACKAGES += \
     q-developer-gsi.avbpubkey \
+    r-developer-gsi.avbpubkey \
+    s-developer-gsi.avbpubkey \