[master] Auto-update dependencies (#253)

Produced via:
  `./hack/update-deps.sh --upgrade && ./hack/update-codegen.sh`
/assign n3wscott vagababov
/cc n3wscott vagababov

Gopkg.lock

@@ -990,14 +990,14 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:dc73d65f40ea05b1d0db96ae5491b6ebc162bb59b3ac5a252cdf87848bc7a4b7"
+  digest = "1:8a965ebe2d83033f6a07e926357f7341b6c7f42e165a3e13c7c8113b953a265b"
   name = "knative.dev/test-infra"
   packages = [
     "scripts",
     "tools/dep-collector",
   ]
   pruneopts = "UT"
-  revision = "000a646b850e6f86e3360e7d376edd9c545d31c1"
+  revision = "891d25bbf859bfc829b515068cc3e167a7fcc528"
 
 [[projects]]
   digest = "1:8730e0150dfb2b7e173890c8b9868e7a273082ef8e39f4940e3506a481cf895c"

vendor/knative.dev/test-infra/scripts/presubmit-tests.sh

@@ -306,6 +306,8 @@ function main() {
     kubectl version --client
     echo ">> go version"
     go version
+    echo ">> python3 version"
+    python3 --version
     echo ">> git version"
     git version
     echo ">> ko version"