docker-compose build が失敗する

現象

dockerfileに修正を入れたところ、

$ docker-compose build

がうまくいかない...

エラー文

Reading package lists...
W: GPG error: http://deb.debian.org/debian buster InRelease: At least one invalid signature was encountered.
E: The repository 'http://deb.debian.org/debian buster InRelease' is not signed.
W: GPG error: http://security.debian.org/debian-security buster/updates InRelease: At least one invalid signature was encountered.
E: The repository 'http://security.debian.org/debian-security buster/updates InRelease' is not signed.
W: GPG error: http://deb.debian.org/debian buster-updates InRelease: At least one invalid signature was encountered.
E: The repository 'http://deb.debian.org/debian buster-updates InRelease' is not signed.

解決方法

使用していないDockerオブジェクトの削除を行いました

$ docker image prune
$ docker container prune

参考
https://docs.docker.jp/config/pruning.html