v1.29.1

This is mostly a bugfix release to address the high load on ntfy.sh. There are now two new options that allow
synchronous batch-writing of messages to the cache. This avoids database locking, and subsequent pileups of waiting
requests.

Bug fixes:

• High-load servers: Allow asynchronous batch-writing of messages to cache via cache-batch-* options (#498/#502)
• Sender column in cache.db shows invalid IP (#503)

Documentation:

• GitHub Actions example (#492, thanks to @ksurl)
• UnifiedPush ACL clarification (#497, thanks to @bt90)
• Install instructions for Kustomize (#463, thanks to @l-maciej)

Other things:

• Put ntfy.sh docs on GitHub pages to reduce AWS outbound traffic cost (#491)
• The ntfy.sh server hardware was upgraded to a bigger box. If you'd like to help out carrying the server cost, sponsorships and donations 💸 would be very much appreciated