package/mongoose: security bump to version 7.1

- Fix CVE-2021-26528: The mg_http_serve_file function in Cesanta
  Mongoose HTTP server 7.0 is vulnerable to remote OOB write attack via
  connection request after exhausting memory pool.
- Fix CVE-2021-26529: The mg_tls_init function in Cesanta Mongoose HTTPS
  server 7.0 and 6.7-6.18 (compiled with mbedTLS support) is vulnerable
  to remote OOB write attack via connection request after exhausting
  memory pool.
- Fix CVE-2021-26530: The mg_tls_init function in Cesanta Mongoose HTTPS
  server 7.0 (compiled with OpenSSL support) is vulnerable to remote OOB
  write attack via connection request after exhausting memory pool.

https://github.com/cesanta/mongoose/releases/tag/7.1



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>