Update 04.lens/01.lens-main/textbook.en.md,...

Update 04.lens/01.lens-main/textbook.en.md, 01.curriculum/01.physics-chemistry-biology/03.Niv3/02.Geometrical-optics/05.paraxial-optics/02.paraxial-optics-simple-elements/04.mirror/01.lens-main/textbook.en.mcd files
Deleted 01.curriculum/01.physics-chemistry-biology/03.Niv3/02.Geometrical-optics/05.paraxial-optics/02.paraxial-optics-simple-elements/04-lens/.gitkeep
1 job from master in 22 seconds (queued for 8 seconds)
Status Job ID Name Coverage
  Deploy
failed #734
deploy

00:00:22

 
Name Stage Failure
failed
deploy Deploy
Sending hook(s) to the production server(s)…
$ curl --no-buffer --silent --show-error https://courses.m3p2.ljbac.com/sync
curl: (60) SSL certificate problem: self signed certificate
More details here: https://curl.haxx.se/docs/sslcerts.html

curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the web page mentioned above.
ERROR: Job failed: exit code 60