Fix cache header for web and theme assets

changelog/unreleased/fix-cache-header.md

@@ -0,0 +1,5 @@
+Bugfix: Let clients cache web and theme assets
+
+We needed to remove "must-revalidate" from the cache-control header to allow clients to cache the web and theme assets.
+
+https://github.com/owncloud/ocis/pull/6914

services/web/pkg/service/v0/service.go

@@ -168,7 +168,7 @@ func (p Web) Static(ttl int) http.HandlerFunc {
 			return
 		}
 
-		w.Header().Set("Cache-Control", fmt.Sprintf("max-age=%s, must-revalidate", strconv.Itoa(ttl)))
+		w.Header().Set("Cache-Control", fmt.Sprintf("max-age=%s", strconv.Itoa(ttl)))
 		w.Header().Set("Expires", expires)
 		w.Header().Set("Last-Modified", lastModified)
 		w.Header().Set("SameSite", "Strict")