Use glamour and termev to render/colorize content (#181)

Merge branch 'master' into use-glamour

select Glamour Theme based on BackgroundColor

Merge branch 'master' into use-glamour

Merge branch 'master' into use-glamour

update termev

update go.mod

label color colorate

use glamour for issue content

Vendor: Add glamour

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/181
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>

vendor/github.com/muesli/termenv/constants_linux.go

@@ -0,0 +1,8 @@
+package termenv
+
+import "golang.org/x/sys/unix"
+
+const (
+	tcgetattr = unix.TCGETS
+	tcsetattr = unix.TCSETS
+)