[roll third_party/pigweed] pw_log: Add utility to encode tokenized message

Adds EncodeTokenizedMessage to support easy translation between
pw_log_tokenized data and the log protobuf format.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/47881

third_party/pigweed Rolled-Commits: c8b939009be35f9..8015cecd2287eeb
Roller-URL: https://ci.chromium.org/b/8844869934770725393
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8844869934770725393
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ib28f6c396a1b7151a164038d2c8945c6cd5312d3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/48483
Reviewed-by: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index c8b9390..8015cec 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit c8b939009be35f93c9781796a8f4fef18dc4c1df
+Subproject commit 8015cecd2287eeb9348d210bf46da567935054af