drone to use go modules

.drone.yml

@@ -9,7 +9,8 @@ pipeline:
     - wget https://git.openprivacy.ca/openprivacy/buildfiles/raw/master/tor/tor
     - wget https://git.openprivacy.ca/openprivacy/buildfiles/raw/master/tor/torrc
     - chmod a+x tor
-    - go list ./... | xargs go get
+    - export GO111MODULE=on
+    - go mod vendor
     - go get -u golang.org/x/lint/golint
   quality:
     image: golang