Update module mattn/go-sqlite3 to v2 (#27)

Author: renovate[bot]

go.mod

@@ -9,11 +9,9 @@ require (
 	github.com/go-xorm/xorm v0.7.9
 	github.com/joho/godotenv v1.3.0
 	github.com/lib/pq v1.3.0
-	github.com/mattn/go-sqlite3 v1.13.0
+	github.com/mattn/go-sqlite3 v2.0.2
 	github.com/stretchr/testify v1.4.0
 	google.golang.org/appengine v1.6.1 // indirect
 )
 
-replace github.com/go-xorm/xorm => github.com/go-xorm/xorm v0.7.9
-
 replace github.com/golang/lint => golang.org/x/lint v0.0.0-20190330180304-d0100b6