Merge pull request kubernetes#126356 from pacoxu/fix-etcd-build-windows

add workdir in etcd Dockerfile for windows

Author: k8s-ci-robot

cluster/images/etcd/Dockerfile.windows

@@ -17,6 +17,7 @@ FROM ${RUNNERIMAGE}
 
 EXPOSE 2379 2380 4001 7001
 
+WORKDIR C:/usr/local/bin
 COPY etcd* etcdctl* /usr/local/bin/
 COPY migrate-if-needed.bat /usr/local/bin/
 COPY migrate /usr/local/bin/migrate.exe