fix: make template build, lint and test cleanly out of the box

build/manifest/main.go

@@ -108,7 +108,7 @@ func findManifest() (*model.Manifest, error) {
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to open %s", manifestFilePath)
 	}
-	defer manifestFile.Close()
+	defer func() { _ = manifestFile.Close() }()
 
 	// Re-decode the manifest, disallowing unknown fields. When we write the manifest back out,
 	// we don't want to accidentally clobber anything we won't preserve.