[third_party/pigweed] Roll 2 commits

68af5d8f586dbaf docs: Merge first-time setup guides into one page
420672d94c74c53 pw_tokenizer: Remove <assert.h> include for static

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: a29bf57c735c7c7..68af5d8f586dbaf
Roller-URL: https://ci.chromium.org/b/8759063528155634065
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I5df7e44e5ef523535613ee89bff4b9d83c6355eb
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/187777
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index a29bf57..68af5d8 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit a29bf57c735c7c787694167d063174f49192a8c6
+Subproject commit 68af5d8f586dbaf68de8050d045f7ad7f1e015fc