feat: drop sourcerer since its no longer maintained

Author: DerSimeon

data/repositories.toml

@@ -687,7 +687,6 @@ repositories = [
   'github.com/solidusio/solidus',
   'github.com/sorbet/sorbet',
   'github.com/sourcegraph/sourcegraph',
-  'github.com/sourcerer-io/sourcerer-app',
   'github.com/spaceuptech/space-cloud',
   'github.com/spack/spack',
   'github.com/splitbrain/dokuwiki',