Add gomod, update travis

.travis.yml

@@ -6,17 +6,27 @@ language: go
 go:
   - 1.11.x
 
+env:
+  global:
+    - GOTFLAGS="-race"
+  matrix:
+    - BUILD_DEPTYPE=gx
+    - BUILD_DEPTYPE=gomod
+
+
+# disable travis install
 install:
-  - make deps
+  - true
 
 script:
   - bash <(curl -s https://raw.githubusercontent.com/ipfs/ci-helpers/master/travis-ci/run-standard-tests.sh)
 
+
 cache:
   directories:
     - $GOPATH/src/gx
+    - $GOPATH/pkg/mod
+    - $HOME/.cache/go-build
 
 notifications:
   email: false
-
-env: GOTFLAGS="-race"

go.mod

+module github.com/libp2p/go-buffer-pool