Update jinja2 and pyzmq, as well as some test/dev dependencies

[kinow]

These changes partially address #2572

Updates jinja2 requirement to 2.11.0 or greater, which effectively means 2.11.1 today, and pyzmq to 18.1.*, which means 18.1.0 today.

Requirements check-list

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Already covered by existing tests.
• Appropriate change log entry included.
• No documentation update required.

[kinow]

pyzmq

pyzmq has fewer changes. A couple related to issues that could affect the WFS or Cylc UI Server (e.g. "handle cancelled futures in asyncio", "fix errors in zmq.Context.destroy() when opening and closing many sockets").

https://pyzmq.readthedocs.io/en/latest/changelog.html#id1

[kinow]

jinja2

This version (2.11.0) still supports 2.7, but is the last one. They have released 2.11.1 too, but that version has a single bug for async templates (no idea what's that, but I guess we are not using it).

The 2.11.0 includes several bug fixes, some new features, and also many changes that affect the behaviour of the the Jinja2 API - though it is not clear if the API changed (i.e. not sure if they removed parameters, renamed functions, or anything that would break API binary? backward compatibility).

Some interesting changes:

• Parentheses around comparisons are preserved, so {{ 2 * (3 < 5) }} outputs “2” instead of “False”.
• Lexing templates with large amounts of whitespace is much faster.
• A new jinja2.ext.debug extension adds a {% debug %} tag to quickly dump the current context and available filters and tests.
• Fix a bug causing deadlocks in LRUCache.setdefault. (:eyes: )
• Float literals can be written with scientific notation, like 2.56e-3.
• Int and float literals can be written with the ‘_’ separator for legibility, like 12_345.
• Fix behavior of loop control variables such as length and revindex0 when looping over a generator.
• Tracebacks for exceptions in templates show the correct line numbers and source for Python >= 3.7. (@hjoliver I suspect it requires something from Py 3.7, so I will check if that works with Cylc 7 and Py27 too before raising the second PR)

https://jinja.palletsprojects.com/en/2.11.x/changelog/#version-2-11-0

[kinow]

Alternatively, this could be

• jinja2>=2.10.1, <2.12.0 (so users could still use 2.10.1 if they prefer?)
• jinja2~=2.11.1 (gives users 2.11.0, or anything after that)

[kinow]

Build passed. Marking as ready for review. Will add another commit with the change log (which means a new build in Travis, but the previous one can be seen here)

[oliver-sanders]

@cylc/core - Jinja2 update - Watch out for any unexpected behaviour changes in workflows.
@TomekTrzeciak - Heads up!

[hjoliver]

Watch out for any unexpected behaviour changes in workflows.

I guess from the Cylc perspective, we support use of Jinja2 in workflow definitions, but it is not up to us to guarantee back-compatibility across Jinja2 releases. Best we can do is warn to watch out!