Sækja Syncthing 2.1.0

Major changes in 2.1
- Devices and folders can now be grouped in the GUI by setting the new
group attribute.
- HTTP and HTTPS proxies with support for CONNECT can now be used, in
addition to the existing support for SOCKS proxies (the environment
variable all_proxy=https://...).
- Block indexing can be turned off for folders where it's more desirable to
optimise for reduced database size and overhead than minimal transfer
size (the blockIndexing attribute on folder configuration).
- GUI login session duration can be configured to be longer or shorter than
the default one week, or set to infinitely long. The cookie path can also
be adjusted. (The sessionCookieDurationS and sessionCookiePath
attributes in the GUI configuration.)
This release is also available as:
- APT repository: https://apt.syncthing.net/
- Docker image: docker.io/syncthing/syncthing:2.1.0 or ghcr.io/syncthing/syncthing:2.1.0
({docker,ghcr}.io/syncthing/syncthing:2 to follow just the major version)

What's Changed

Fixes
- fix(stdiscosrv): close file descriptor on flush error in write by @cuiweixie in #10615
- fix(gui): disable autocomplete for folder password by @bt90 in #10342
- fix(protocol): limit size of incoming request messages by @calmh in #10629
- fix(gui): don't show local device under remote devices (ref #10563) by @maen-bn in #10631
- fix(gui): order folders alphabetically and ensure local device stays hidden (ref #10563, ref #10631) by @maen-bn in #10637
- fix(gui): fallback to folder ID when label is empty in remove dialog by @RealCharlesChia in #10657
- fix(gui): fix tabs visually disabled but still clickable during ignore patterns setup (fixes #10634) by @JRNitre in #10651
- fix(strelaysrv): properly use bind address for outgoing requests (fixes #10658) by @calmh in #10659
- fix(stdiscosrv): only read certificate proxy headers with --http by @calmh in #10674

Features
- feat(gui, config): support simple folder grouping (fixes #2070) by @maen-bn in #10563
- feat: make http session cookie path & duration configurable by @vvaswani in #10632
- feat(dialer): add HTTP/HTTPS proxy support via CONNECT by @luizluca in #10572
- feat: make block indexing configurable by @calmh in #10608

Other
- chore: remove tracking inode change time by @calmh in #10579
- build(deps): temporarily switch to fork of gateway discovery library (fixes #10593) by @marbens-arch in #10594
- build: extract github.ref_name expression to env mapping by @dagecko in #10624
- build: pin 20 third-party actions to immutable commit SHAs by @dagecko in #10625
- build: have dependabot group PRs and use cooldown by @calmh in #10630
- chore: trivial fixes by @calmh in #10650
- chore(model): more efficient tracking of renames during scan by @calmh in #10653
- chore(model): deflake cluster config tests by @calmh in #10662
- chore(model): deflake TestCompletionEmptyGlobal by @calmh in #10663
- chore(scanner): deflake TestStopWalk by @calmh in #10664
- build: parallelise linux builds slightly by @calmh in #10666
- chore(api): deflake TestHTTPLogin on Windows by @calmh in #10667
- chore(api): use ldap package escape functions by @calmh in #10672
- build: only run the periodic build jobs in the syncthing org by @calmh in #10675
- build(deps): update dependencies by @calmh in #10683
- chore(model): slightly improve handling of pulling empty blocks by @calmh in #10679
- chore(gui): upgrade jQuery to 3.7.1 to fix CVE-2020-11022, CVE-2020-11023, CVE-2015-9251 by @Umer-Azaz in #10673
- chore(fs): remove unused SymlinksSupported() method by @calmh in #10684

New Contributors
- @cuiweixie made their first contribution in #10615
- @dagecko made their first contribution in #10624
- @maen-bn made their first contribution in #10563
- @RealCharlesChia made their first contribution in #10657
- @JRNitre made their first contribution in #10651
- @vvaswani made their first contribution in #10632
- @luizluca made their first contribution in #10572
- @Umer-Azaz made their first contribution in #10673