syncthing: revbump for go 1.21

srcpkgs/syncthing/template

@@ -1,7 +1,7 @@
 # Template file for 'syncthing'
 pkgname=syncthing
 version=1.23.7
-revision=1
+revision=2
 build_style=go
 go_import_path="github.com/syncthing/syncthing"
 go_package="
@@ -19,6 +19,7 @@ distfiles="https://github.com/syncthing/${pkgname}/archive/v${version}.tar.gz"
 checksum=cc36d6244590f0eeaa1df6f465b617dd7fdbee3dae434d55b272b25580f6e53b
 
 pre_build() {
+	export GOTOOLCHAIN="go1.20.7"
 	GOARCH= go generate \
 		github.com/syncthing/syncthing/lib/api/auto \
 		github.com/syncthing/syncthing/cmd/strelaypoolsrv/auto