Fix failing Travis CI jobs (#494)

* Fix building with Go 1.12 in Travis CI

Travis clones the source code under GOPATH and uses GO11MODULE=auto
by default, which disables modules when Go 1.12 is being used.

This is now a breaking problem because the master of
github.com/stretchr/testify/assert requires Go 1.13.  Using a
specific version of assert requires either vendoring all
dependencies or forcing Go 1.12 to use modules.

* Fix path to a distribution public key that no longer exists

Co-authored-by: Cody Jones <[email protected]>

Author: CodyDWJones

.travis.yml

@@ -7,11 +7,9 @@ go:
 
 go_import_path: gopkg.in/rethinkdb/rethinkdb-go.v6
 
-install: go get -t ./...
-
 before_script:
-  - source /etc/lsb-release && echo "deb http://download.rethinkdb.com/apt $DISTRIB_CODENAME main" | sudo tee /etc/apt/sources.list.d/rethinkdb.list
-  - wget -qO- http://download.rethinkdb.com/apt/pubkey.gpg | sudo apt-key add -
+  - source /etc/lsb-release && echo "deb https://download.rethinkdb.com/repository/ubuntu-$TRAVIS_DIST $TRAVIS_DIST main" | sudo tee /etc/apt/sources.list.d/rethinkdb.list
+  - wget -qO- https://download.rethinkdb.com/repository/raw/pubkey.gpg | sudo apt-key add -
   - sudo apt-get update
   - sudo apt-get install rethinkdb
   - rethinkdb > /dev/null 2>&1 &
@@ -20,6 +18,7 @@ before_script:
   - rethinkdb --port-offset 3 --directory rethinkdb_data3 --join localhost:29016 > /dev/null 2>&1 &
 
 script:
-  - go test -race .
-  - go test -tags='cluster' -short -race -v ./...
-  - GOMODULE111=off go test .
+  - GO111MODULE=on go test -race .
+  - GO111MODULE=on go test -tags='cluster' -short -race -v ./...
+  - GO111MODULE=on go test .
+

go.mod

@@ -23,4 +23,5 @@ require (
 	gopkg.in/yaml.v2 v2.2.8 // indirect
 )
 
-go 1.14
+go 1.12
+