Roll external/abseil_cpp/ a28c4b582..fd8b35b9a (6 commits) (#5955)

https://github.com/abseil/abseil-cpp/compare/a28c4b5827fe...fd8b35b9aa40

Created with:
  roll-dep external/abseil_cpp

Co-authored-by: GitHub Actions[bot] <>
diff --git a/DEPS b/DEPS
index 4b78d81..8d51a29 100644
--- a/DEPS
+++ b/DEPS
@@ -3,7 +3,7 @@
 vars = {
   'github': 'https://github.com',
 
-  'abseil_revision': 'a28c4b5827fefee822c34d42e0c67d6889942471',
+  'abseil_revision': 'fd8b35b9aa409759d9c5b070a5604849c0a274cc',
 
   'effcee_revision': 'e63a164aa0a40a04ddca2c18976819668b5a47a8',