CI: go mod download before tests

Author: jubr

.circleci/config.yml

@@ -190,6 +190,8 @@ jobs:
             go get     github.com/mattn/goveralls
             go install github.com/mattn/goveralls
             go get golang.org/x/crypto/ssh/terminal@v0.0.0-20210921155107-089bfa567519
+            : prepare for 'go test'
+            go mod download
       # https://circleci.com/developer/orbs/orb/circleci/go
       - go/test: # Runs 'go test ./...' but includes extensive parameterization for finer tuning.
           covermode: atomic