ci: update golangci-lint and check go modules (#12)

* chore: update golangci-lint.
* chore: validate go modules and vendor.
* fix: go modules files.
* fix: vendor folder content.

.golangci.yaml

@@ -20,4 +20,14 @@ linters:
     - gocritic
     - gochecknoinits
     - gochecknoglobals
-    - typecheck # Go 1.13 incompatible pending new golangci-lint binary release
+    - gomnd
+    - wsl
+
+issues:
+  exclude-use-default: true
+  max-per-linter: 0
+  max-same-issues: 0
+  # The following excludes are considered false-positives/known-OK.
+  exclude-rules:
+    - path: tlsalpnone.go
+      text: '`marshalling` is a misspelling of `marshaling`'

.travis.yml

@@ -1,16 +1,26 @@
 language: go
+
 go:
   - "stable"
 
+cache:
+  directories:
+    - $GOPATH/pkg/mod
+
 # Override the base install phase so that the project can be installed using
 # `-mod=vendor` to use the vendored dependencies
 install:
   # Install `golangci-lint` using their installer script
-  - curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go env GOPATH)/bin v1.17.1
+  - curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go env GOPATH)/bin v1.23.3
   # Install `cover` and `goveralls` without `GO111MODULE` enabled so that we
   # don't download project dependencies and just put the tools in $GOPATH/bin
   - GO111MODULE=off go get golang.org/x/tools/cmd/cover
   - GO111MODULE=off go get github.com/mattn/goveralls
+  - go mod tidy
+  - git diff --exit-code go.mod
+  - git diff --exit-code go.sum
+  - go mod download
+  - go mod vendor
   - go install -mod=vendor -v -race ./...
 
 script:

go.mod

@@ -1,5 +1,7 @@
 module github.com/letsencrypt/challtestsrv
 
+go 1.13
+
 require (
 	github.com/miekg/dns v1.1.1
 	golang.org/x/crypto v0.0.0-20181203042331-505ab145d0a9 // indirect