Use Go1.11 module (#5743)

* Migrate to go modules

* make vendor

* Update mvdan.cc/xurls

* make vendor

* Update code.gitea.io/git

* make fmt-check

* Update github.com/go-sql-driver/mysql

* make vendor

vendor/golang.org/x/text/language/Makefile

@@ -0,0 +1,16 @@
+# Copyright 2013 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+CLEANFILES+=maketables
+
+maketables: maketables.go
+	go build $^
+
+tables:	maketables
+	./maketables > tables.go
+	gofmt -w -s tables.go
+
+# Build (but do not run) maketables during testing,
+# just to make sure it still compiles.
+testshort: maketables