Your bundle is locked to mimemagic (0.3.5), but that version could not be found

herokuにrailsアプリをpushしてreview appを作成したら急に上記エラーが発生しました

Installing dependencies using bundler 2.2.11
       Running: BUNDLE_WITHOUT='development:test' BUNDLE_PATH=vendor/bundle BUNDLE_BIN=vendor/bundle/bin BUNDLE_DEPLOYMENT=1 bundle install -j4
       Fetching gem metadata from https://rubygems.org/............
       Your bundle is locked to mimemagic (0.3.5), but that version could not be found
       in any of the sources listed in your Gemfile. If you haven't changed sources,
       that means the author of mimemagic (0.3.5) has removed it. You'll need to update
       your bundle to a version other than mimemagic (0.3.5) that hasn't been removed
       in order to install.
       Bundler Output: Fetching gem metadata from https://rubygems.org/............
       Your bundle is locked to mimemagic (0.3.5), but that version could not be found
       in any of the sources listed in your Gemfile. If you haven't changed sources,
       that means the author of mimemagic (0.3.5) has removed it. You'll need to update
       your bundle to a version other than mimemagic (0.3.5) that hasn't been removed
       in order to install.

調べてみたら、どうやらmimemagicというGemが公開停止したらしく、それが原因でEC2とかHerokuとかで落ちてるっぽいです

とりあえずこちらを実行して解決できました

bundle update mimemagic

参考記事

[Rails] bundle installがYour bundle is locked to mimemagic (0.3.5)…で落ちる

Dependency on mimemagic 0.3.x no longer valid #41750