flake8: Suppress "E731 do not assign a lambda expression, use a def"
flake8: Suppress "E731 do not assign a lambda expression, use a def"

The Google Python Style Guide [1] says that lambdas are OK for
one-liners. All the current usages are one-liners, so let's just
suppress it.

[1] http://google.github.io/styleguide/pyguide.html#210-lambda-functions

Change-Id: I404c7a8e5e71870caf0f4604862cbf01db495863
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/255038
Tested-by: David Pursehouse <e7b5c6a4a3dbaca972851f8c075e19915752593f@collab.net>
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@google.com>

GerritCodeReview/git-repo,lipro-yocto/git-repo,GerritCodeReview/git-repo,codetutil/git-repo,codetutil/git-repo,aosp-mirror/tools_repo,TheQtCompany/git-repo,mer-tools/git-repo,lipro-yocto/git-repo,couchbasedeps/git-repo,TheQtCompany/git-repo,couchbasedeps/git-repo,lewixliu/git-repo,mer-tools/git-repo,lewixliu/git-repo,aosp-mirror/tools_repo