roll: third_party/pigweed: pw_env_setup: Update clang next version

Make toolchain roll canary builders to target the latest clang toolchain
revision.

Original-Bug: 366374135
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/235612
Docs-Not-Needed: Prabhu Karthikeyan Rajasekaran <prabhukr@google.com>

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 900a866bd4fc169..a60f57b2e1cea33
Roller-URL: https://ci.chromium.org/b/8736887551654326241
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: If330ccc428b685aefb1f287d3cd54766a86a7878
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/235673
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.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 900a866..a60f57b 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 900a866bd4fc1692cd6e9df6f19ad7038eb30ecd
+Subproject commit a60f57b2e1cea330a5661bfbc96f275278718b50