fixing travis jobs

Author: sorobon

.travis.yml

@@ -3,6 +3,10 @@ language: python
 python: 3.9
 services:
 - docker
+before_install:
+  - mkdir -vp ~/.docker/cli-plugins/
+  - curl --silent -L "https://github.com/docker/buildx/releases/download/v0.3.0/buildx-v0.3.0.linux-amd64" > ~/.docker/cli-plugins/docker-buildx
+  - chmod a+x ~/.docker/cli-plugins/docker-buildx
 install:
 - pip install pipenv
 - pipenv sync