Update instructions

Assuming your checked out version of musicbrainz-docker is v-2024-05-13-mbdb29-pg16 or later, then just run:

git fetch --tags origin && \
git checkout v-2025-05-05.0 && \
sudo docker-compose up --build -d

Only change

• Upgrade MusicBrainz Server to v-2025-05-05.0