v0.2

CHANGES:

The main new feature is that OCurrent now evaluates pipelines incrementally.
This means that services with large pipelines (such as ocaml-ci, with around
10,000 stages) can decide what they need to do without using an excessive
amount of CPU time.

• Replace changed promises with Engine.update (@talex5, #135)
• Evaluate pipelines incrementally (@talex5, #144)
• Avoid unnecessary re-evaluations in Current.list_map (@talex5, #148)
• Change the representation of terms to support incremental evaluation (@talex5, #150)

Documentation:

• Added Internals wiki
  page explaining how OCurrent works.
• Update README.md to link the API Docs (@shonfeder, #145)
• Fix typo in README ("about" -> "above") (@smolck, #100)

Docker plugin:

• Add support for run-arguments in docker plugin (@MagnusS, #96)
• Add ?build_args parameter to Current_docker build (@SquidDev, #102)
• Allow alternative Dockerfile filenames in Docker.build (@talex5, #111)
• Add Docker.pread to get container stdout as a string (@kit-ty-kate, #120)
• Make it easier to add custom Docker commands (@talex5, #130)

Git plugin:

• Git.fetch: don't take repository lock until the job starts (@talex5, #116)

GitHub plugin:

• Add Github.Api.head_of to track individual branches (@talex5, #114)
• Expose the low-level refs function to get access to branch names and PR
  numbers (@talex5, #123)
• Add Commit.uri to make links back to GitHub (@talex5, #131)
• Better error if setting a GitHub commit status fails (@talex5, #151)
• Only refresh the repository that generated the webhook event, not all of them (@talex5, #156)

Web UI:

• Use routes library to simplify routing (@talex5, #160)
• Add "/jobs" page with information about active jobs (@talex5, #125)
• Mark HTML pages as UTF-8 (@talex5, #128)

Dependencies:

• Update to new Alcotest API (@talex5, #121)
• Use mirage-crypto instead of nocrypto (@hannesm, #161)

Bug fixes:

• Fix analysis with hidden catch/state nodes (@talex5, #134)
• Allow cancelling a job while waiting for confirmation (@talex5 #137)
• Fix merging of error states for pairs (@talex5, #147)

Metrics:

• Report Prometheus metrics for pipeline stage states (@talex5, #115)
• Report metric for cache evaluations (@talex5, #143)

Build improvements:

• Make dune transitive dependencies explicit (@craigfe, #97)
• Add OCaml-CI status badge to the README (@craigfe, #107)

Other:

• Explicitly enumerate accepted --confirm values (@craigfe, #108)
• Rename Input to Primitive and simplify the API (@talex5, #154)
• Call Lwt_main.yield while testing log patterns (@talex5, #155)
• Add Current.collapse to allow collapsing parts of diagrams (@talex5, #152)
• Add Current.with_context to help with diagram layout (@talex5, #159)