chore: release 0.13.1

[github-actions]

🤖 I have created a release *beep* *boop*

0.13.1 (2021-10-16)

Bug Fixes

• *.opam: Make common deps constraints uniform & Add missing deps (26a50ef)
• API: Fix listing exercise status when the status list hasn't been initialized; Fix #314 (3c781cb)
• grader: Display negative numbers with mandatory parens; Fix #440 (35941b5)
• UI: Cleanup duplicate, inconsistent camel logos (03d871a)
• UI: Display Actions=teacher_menubar properly in responsive mode; Fix #444 (#450) (b6d44db)
• UI: Fix CSS bug regarding the loading animation (#445) (881982a)
• UI: Increase timeout during grading (3cb9dd1)
• UI: Update one fr translation (06a71ae)

Dependencies

• Fix version of dune package (w.r.t. that of dune-project file) (7c11083)

Documentation

• tests/README.md: Add hint for test case generation (19477a5)

Tests

• Add Dockefile.test-server to repro issue with learn-ocaml.opam (6d86ce6)
• Add test to repro issue #440 (07033c9)

CI/CD

• build-and-test.yml: Add ocamlsf/learn-ocaml:0.13.0 in client test matrix (6c21d9c)
• Ensure release-please triggers docker/build-push-action jobs (#443) (71c3590)
• Ensure the CD-related workflows won't run on forks (#446) (6b8c49b)

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[erikmd]

just FYI @yurug,
this release PR was opened fully automatically (no need for git commit --allow-empty -m "…" -m "Release-As: …")
because another PR was merged with commits having prefix fix: etc. :)

[yurug]

Oh, that script is even more convenient than we thought!

[github-actions]

🤖 Release is at https://github.com/ocaml-sf/learn-ocaml/releases/tag/v0.13.1 🌻