9.3 release doesn't work hosted off github

[chatman]

Earlier, Solr used to be able to use repos hosted off a Github repo directly, e.g. https://raw.githubusercontent.com/searchscale/dataimporthandler/master/repo/.

Now, Solr 9.3.0 fails, claiming it expected application/json mime type and got text/plain. Hence, data-import-handler 9.3 release is unusable via the package manager. Reported by @sajiljosephs .