DEPS: Bump abseil & protobuf

Needed for C++20 support

Change-Id: Ie04f159fc425ca25a244121dc546897337637062
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/148420
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
diff --git a/DEPS b/DEPS
index ab3d7be..fbeb3bf 100644
--- a/DEPS
+++ b/DEPS
@@ -108,7 +108,7 @@
   },
 
   'third_party/abseil-cpp': {
-    'url': '{chromium_git}/chromium/src/third_party/abseil-cpp@bc3ab29356a081d0b5dd4ac55e30f4b45d8794cc',
+    'url': '{chromium_git}/chromium/src/third_party/abseil-cpp@4ef9b33175828ea46d091e7e5ec28259d39a8ba5',
   },
 
   # Dependencies required for testing
@@ -129,7 +129,7 @@
   },
 
   'third_party/protobuf': {
-    'url': '{chromium_git}/external/github.com/protocolbuffers/protobuf.git@fde7cf7358ec7cd69e8db9be4f1fa6a5c431386a',
+    'url': '{chromium_git}/external/github.com/protocolbuffers/protobuf.git@2b673bbb57e34fe1bd4570f726fc86b769a3a3d2',
   },
 }