upgrade to use testfixtures v3 (#11904)

* upgrade to use testfixtures v3

* simplify logic

* make vendor

* update per @lunny

* Update templates/repo/empty.tmpl

* Update templates/repo/empty.tmpl

Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/github.com/mattn/go-sqlite3/sqlite3_opt_preupdate.go

@@ -0,0 +1,20 @@
+// Copyright (C) 2019 G.J.R. Timmer <gjr.timmer@gmail.com>.
+// Copyright (C) 2018 segment.com <friends@segment.com>
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// +build cgo
+
+package sqlite3
+
+// SQLitePreUpdateData represents all of the data available during a
+// pre-update hook call.
+type SQLitePreUpdateData struct {
+	Conn         *SQLiteConn
+	Op           int
+	DatabaseName string
+	TableName    string
+	OldRowID     int64
+	NewRowID     int64
+}