build(deps): bump third_party/abseil-cpp from `e968256` to `56d3f22` (#2337)

Bumps [third_party/abseil-cpp](https://github.com/abseil/abseil-cpp) from `e968256` to `56d3f22`.
- [Release notes](https://github.com/abseil/abseil-cpp/releases)
- [Commits](https://github.com/abseil/abseil-cpp/compare/e968256406fd7898d7fde880e31e54b041d32a7e...56d3f227154af7a646302ae4a0891f14a2d3616b)

---
updated-dependencies:
- dependency-name: third_party/abseil-cpp
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/abseil-cpp b/third_party/abseil-cpp
index e968256..56d3f22 160000
--- a/third_party/abseil-cpp
+++ b/third_party/abseil-cpp
@@ -1 +1 @@
-Subproject commit e968256406fd7898d7fde880e31e54b041d32a7e
+Subproject commit 56d3f227154af7a646302ae4a0891f14a2d3616b