convert from dep to go mod

Closes #30

.travis.yml

@@ -5,19 +5,22 @@ services:
 language: go
 go:
   - "1.11.x"
+cache:
+  directories:
+    - $GOPATH/pkg
+    - .autoconf
+    - vendor
 
-before_install:
-  # Setup dependency management tool
-  - curl -L -s https://github.com/golang/dep/releases/download/v0.5.0/dep-linux-amd64 -o $GOPATH/bin/dep
-  - chmod +x $GOPATH/bin/dep
+env:
+  global:
+    - GOFLAGS=-mod=vendor GO111MODULE=on
 
 install:
 # This script is used by the Travis build to install a cookie for
 # go.googlesource.com so rate limits are higher when using `go get` to fetch
 # packages that live there.
 # See: https://github.com/golang/go/issues/12933
 - bash scripts/gogetcookie.sh
-- dep ensure
 
 script:
 - make test

GNUmakefile

@@ -40,9 +40,6 @@ fmtcheck:
 errcheck:
 	@sh -c "'$(CURDIR)/scripts/errcheck.sh'"
 
-vendor-status:
-	@dep status
-
 test-compile:
 	@if [ "$(TEST)" = "./..." ]; then \
 		echo "ERROR: Set TEST to a specific package. For example,"; \
@@ -65,5 +62,5 @@ ifeq (,$(wildcard $(GOPATH)/src/$(WEBSITE_REPO)))
 endif
 	@$(MAKE) -C $(GOPATH)/src/$(WEBSITE_REPO) website-provider-test PROVIDER_PATH=$(shell pwd) PROVIDER_NAME=$(PKG_NAME)
 
-.PHONY: build sweep test testacc vet fmt fmtcheck errcheck vendor-status test-compile website website-test
+.PHONY: build sweep test testacc vet fmt fmtcheck errcheck test-compile website website-test