cpython3 3.8.10.chromium.20 to depot_tools bleeding edge.

Bug: 1220743
Change-Id: I9ba3f445c72d802925bf6e042dc1785fe4f08867
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3034710
Auto-Submit: Brian Ryner <bryner@google.com>
Commit-Queue: Dirk Pranke <dpranke@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>

bootstrap/manifest_bleeding_edge.txt

@@ -21,7 +21,7 @@ $VerifiedPlatform windows-386 windows-amd64 linux-amd64 mac-amd64
 infra/3pp/tools/cpython/${platform} version:2@2.7.18.chromium.39
 
 @Subdir python3
-infra/3pp/tools/cpython3/${platform} version:2@3.8.10.chromium.19
+infra/3pp/tools/cpython3/${platform} version:2@3.8.10.chromium.20
 
 @Subdir git
 infra/3pp/tools/git/${os}-${arch} version:2@2.30.2.chromium.6