[roll third_party/pigweed] pw_i2c: Fix accidental c++2a

This should have been c++20 for the cpp_std.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/176511

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 2fa809b25279801..ddb745611e11dce
Roller-URL: https://ci.chromium.org/b/8766969407438314641
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I967a3397ac7c7b5f97a00fb61afe19e0aa7dde49
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/176591
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 2fa809b..ddb7456 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 2fa809b2527980187e6ea9a2f3bb8e40c8d793f1
+Subproject commit ddb745611e11dce8ab50138f6aacd39d988c2729