[roll third_party/pigweed] pw_proto_compiler: strip_import_prefix + options

Fix the handling of nanopb and pwpb options files in the presence of the
strip_import_prefix attribute on proto_library.

Original-Bug: b/328311416
Original-Fixed: b/326636665
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/194949

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 8a6f44e41e80bf8..081fda08421df2a
Roller-URL: https://ci.chromium.org/b/8754162065723394065
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I23575fc8166d4e6b29553b130f2f325651402016
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/195143
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 8a6f44e..081fda0 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 8a6f44e41e80bf8819312b1a9fc1a115e38ae9f2
+Subproject commit 081fda08421df2ad3592be7d8cfd138566f19685