go: update most dependencies to the latest version

It's a lot of work for dependabot for our outdated deps, let's
help it by making one huge manual update.

Signed-off-by: Ondřej Budai <ondrej@budai.cz>

vendor/github.com/dimchansky/utfbom/.travis.yml

@@ -1,17 +1,28 @@
 language: go
+sudo: false
 
 go:
-  - '1.10'
-  - '1.11'
+  - 1.10.x
+  - 1.11.x
+  - 1.12.x  
+  - 1.13.x
+  - 1.14.x
+  - 1.15.x
 
-# sudo=false makes the build run using a container
-sudo: false
+cache:
+  directories:
+    - $HOME/.cache/go-build
+    - $HOME/gopath/pkg/mod
+
+env:
+  global:
+    - GO111MODULE=on
 
 before_install:
   - go get github.com/mattn/goveralls
   - go get golang.org/x/tools/cmd/cover
   - go get golang.org/x/tools/cmd/goimports
-  - go get github.com/golang/lint/golint
+  - go get golang.org/x/lint/golint
 script:
   - gofiles=$(find ./ -name '*.go') && [ -z "$gofiles" ] || unformatted=$(goimports -l $gofiles) && [ -z "$unformatted" ] || (echo >&2 "Go files must be formatted with gofmt. Following files has problem:\n $unformatted" && false)
   - golint ./... # This won't break the build, just show warnings

vendor/github.com/dimchansky/utfbom/LICENSE

@@ -186,7 +186,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright {yyyy} {name of copyright owner}
+   Copyright (c) 2018-2020, Dmitrij Koniajev (dimchansky@gmail.com)
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

vendor/github.com/dimchansky/utfbom/go.mod

@@ -1 +1 @@
-module github.com/dimchansky/utfbom
+module github.com/dimchansky/utfbom