package/flac: security bump to version 1.3.4

This release mostly fixes (security related) bugs including:
 - Fix 12 decoder bugs found by oss-fuzz, including CVE-2020-0499
 - Fix encoder bug CVE-2021-0561

Also:
 - Replace first patch which was reverted by
   https://github.com/xiph/flac/commit/4fbb6d4f2ecf2a96c17ea9880108409f852c08a9
 - Disable stack protection (enabled by default since
   https://github.com/xiph/flac/commit/f706f2832270a0b7851cdffe62ad37acda9423fe)
 - Drop md5 which is not provided anymore
 - Update indentation in hash file (two spaces)

https://github.com/xiph/flac/releases/tag/1.3.4



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