GHSA-c57f-mm3j-27q9: Astro: Cache Poisoning due to incorrect error handling when if-match header is malformed

Astro versions 5.14.1 and Node 9.4.4 have a cache poisoning vulnerability where sending a malformed `if-match` header (a request validation header) to static JavaScript or CSS files causes the server to return a 500 error with a one-year cache duration instead of the correct 412 error with no cache headers. This means all future requests to that file get cached error responses, breaking the application until the cache expires.