Syncthing 1.2.0 (64-bit)

What's new in this version:

Important notes:
- This release does not interoperate with Syncthing 0.14.45 or older
- This release adds QUIC with NAT traversal as a new transport protocol. TCP
is usually more performant and remains the preferred way of connection when
possible
- This release adds automatic crash reporting
- This release makes large / variable block size the only available mode of
operation; small / fixed blocks are deprecated
- This release reverts the version naming change in #4586 (v1.1.4). Versions are now named with the time of their archiving, and the file modification time is unchanged when archiving. An exception to this is the "Trashcan" versioner which does not modify the name - instead it does set the file modification time the time of archiving

Bugfixes:
- panic: bug: ClusterConfig called on closed or nonexistent connection
- Filesystem watching failed when parent folder is not listable
- Connection error after closing failed items list and opening another list
- Verioner cleanup looks at the wrong time
- Support bundle doesn't include errors list, instead printing an error
- Scan failure blocks "Rescan" button
- Spurious need to "revert" nonexistent changes with Receive Only folder on Android
- Panic when folder disappears while scanning
- Shutdown takes too long, triggering fmut deadlock panic
- Puller complains about invalid filenames which are long gone

Enhancements:
- Automatic error log sending to dev. team
- Show last connection error per discovered address
- Use of QUIC for transport
- Dockerfile ENTRYPOINT doesn't pass along extra arguments from "docker run"
- Handle fatal watch errors gracefully
- WebUI table column widths broken on narrow displays

Other issues:
- Dead link in README.md
- TestPullInvalidIgnoredSR/SO is flaky