add vendoring

vendor/github.com/mattn/go-sqlite3/sqlite3_opt_column_metadata.go

@@ -0,0 +1,21 @@
+// +build sqlite_column_metadata
+
+package sqlite3
+
+/*
+#ifndef USE_LIBSQLITE3
+#cgo CFLAGS: -DSQLITE_ENABLE_COLUMN_METADATA
+#include <sqlite3-binding.h>
+#else
+#include <sqlite3.h>
+#endif
+*/
+import "C"
+
+// ColumnTableName returns the table that is the origin of a particular result
+// column in a SELECT statement.
+//
+// See https://www.sqlite.org/c3ref/column_database_name.html
+func (s *SQLiteStmt) ColumnTableName(n int) string {
+	return C.GoString(C.sqlite3_column_table_name(s.s, C.int(n)))
+}