Add vendor directory and update vendorHash to null

vendor/github.com/jackc/pgx/v5/pgconn/README.md

@@ -0,0 +1,29 @@
+# pgconn
+
+Package pgconn is a low-level PostgreSQL database driver. It operates at nearly the same level as the C library libpq.
+It is primarily intended to serve as the foundation for higher level libraries such as https://github.com/jackc/pgx.
+Applications should handle normal queries with a higher level library and only use pgconn directly when required for
+low-level access to PostgreSQL functionality.
+
+## Example Usage
+
+```go
+pgConn, err := pgconn.Connect(context.Background(), os.Getenv("DATABASE_URL"))
+if err != nil {
+	log.Fatalln("pgconn failed to connect:", err)
+}
+defer pgConn.Close(context.Background())
+
+result := pgConn.ExecParams(context.Background(), "SELECT email FROM users WHERE id=$1", [][]byte{[]byte("123")}, nil, nil, nil)
+for result.NextRow() {
+	fmt.Println("User 123 has email:", string(result.Values()[0]))
+}
+_, err = result.Close()
+if err != nil {
+	log.Fatalln("failed reading result:", err)
+}
+```
+
+## Testing
+
+See CONTRIBUTING.md for setup instructions.