fix(ci): append instead of overwrite, causing open-brace to be disapp…

…eared

.github/workflows/validate-renovate.yml

@@ -29,8 +29,9 @@ jobs:
           echo '{' >> "$H"
           # let's do main part, but avoid pipefail
           (npx --yes --package "$package" -- renovate-config-validator --strict || true)\
-            | ruby -e 'File.open(ENV[?H], ?w) {|r| while gets; puts $_; $> = r if $_.strip == "WARN: Config migration necessary" ;end; }'
+            | ruby -e 'File.open(ENV[?H], ?a) {|r| while gets; puts $_; $> = r if $_.strip == "WARN: Config migration necessary" ;end; }'
           echo '}' >> "$H"
+          
           echo "---"
           echo "Collected output: $H"
           cat "$H"