build(deps): bump third_party/migen from `12eb563` to `f3e9145` (#3096)

Bumps [third_party/migen](https://github.com/m-labs/migen) from `12eb563` to `f3e9145`.
- [Release notes](https://github.com/m-labs/migen/releases)
- [Commits](https://github.com/m-labs/migen/compare/12eb563e89ffc4a5e046239171207c9476f8f665...f3e9145c9825514a1b4225378936569da4df8e12)

---
updated-dependencies:
- dependency-name: third_party/migen
  dependency-type: direct:production
...

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Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/migen b/third_party/migen
index 12eb563..f3e9145 160000
--- a/third_party/migen
+++ b/third_party/migen
@@ -1 +1 @@
-Subproject commit 12eb563e89ffc4a5e046239171207c9476f8f665
+Subproject commit f3e9145c9825514a1b4225378936569da4df8e12