Update README.md

Author: syahzuan

cmd/migrate/README.md

@@ -27,8 +27,8 @@ $ scoop install migrate
 ### Linux (*.deb package)
 
 ```bash
-$ curl -L https://packagecloud.io/golang-migrate/migrate/gpgkey | apt-key add -
-$ echo "deb https://packagecloud.io/golang-migrate/migrate/ubuntu/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/migrate.list
+$ curl -L https://packagecloud.io/golang-migrate/migrate/gpgkey | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/golang-migrate.gpg
+$ echo "deb https://packagecloud.io/golang-migrate/migrate/ubuntu/ $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/migrate.list
 $ apt-get update
 $ apt-get install -y migrate
 ```