cos/tools: remove cos-ova-converter to avoid future releases

BUG=b/215744908

Change-Id: I051601dc22c572ac163fa1eb9692c03c6da0e5c9
Reviewed-on: https://cos-review.googlesource.com/c/cos/tools/+/28320
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Tested-by: Varsha Teratipally <teratipally@google.com>
Cloud-Build: GCB Service account <228075978874@cloudbuild.gserviceaccount.com>
diff --git a/release/release-versions.yaml b/release/release-versions.yaml
index c75cffb..9cc7af6 100644
--- a/release/release-versions.yaml
+++ b/release/release-versions.yaml
@@ -21,9 +21,3 @@
   build_commit: "22b2b5d28b96e96a92ef57730c5ca29d399642ed"
   release_tags:
     - "v2.0.17"
-- staging_container_name: "cos-ova-converter"
-  release_container_name: "cos-ova-converter"
-  build_commit: "2d81698f7cf6ff33fa78fe5fe0254e113712a021"
-  release_tags:
-  - "latest"
-  - "1.0.0"