feat: Add ecosystem support for cleanstart (#4646)

Signed-off-by: community-admin <community-admin@cleanstart.com>
Co-authored-by: Rex P <106129829+another-rex@users.noreply.github.com>

Author: cleanstart-community-admin

osv/ecosystems/_ecosystems.py

@@ -42,6 +42,7 @@
     'Bioconductor': Bioconductor,
     'Bitnami': SemverEcosystem,
     'Chainguard': APK,
+    'CleanStart': APK,
     'CRAN': CRAN,
     'crates.io': SemverEcosystem,
     'Debian': Debian,