[roll third_party/pigweed] pw_protobuf: Fixes Python path on LUCI/presubmit

This change passes through the PATH environment variable to Bazel
allowing pw_env_setup to override the system Python installation. This
partially fixes pwbug/437 allowing for Protobuf/RPC rules to be run on
the CI and locally. This however introduces a dependency for
Pigweed/Bazel on pw_env_setup or system Python-3.6+ for downstream
projects.

Original-Bug: 437
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/57660

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 6ae057c48564ac4..0f6099ff8dfd886
Roller-URL: https://ci.chromium.org/b/8838006455573725393
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8838006455573725393
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I6cf27e65a4c816c9e99ff2493925551471d4d677
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/58082
Bot-Commit: 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 6ae057c..0f6099f 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 6ae057c48564ac41c288c3f211bbe5863f68ed5b
+Subproject commit 0f6099ff8dfd886461fc8c9f0738f18cb4df61c9