Fix missing f-strings, deprecated datetime, stale pylint directives

- Add f-prefix to three RuntimeError format strings in attributes.py
  that were printing literal {self.name} instead of the attribute name
- Replace deprecated datetime.utcnow() with datetime.now(timezone.utc)
  in all four export functions
- Update hardcoded version fallback from 1.1.0 to 2.0.0 and narrow
  bare except to except Exception in exporters.py
- Remove obsolete pylint no-self-use directives from reporting.py
  and iznn/__init__.py

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Add What's New in 2.0 section to README

Briefly describe the per-node evolvable time constants change for
CTRNNs, note the breaking API change, and link to the detailed
CTRNN-CHANGES.pdf writeup.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Release version 1.1.0

Release version 1.0.0

This revision was uploaded to PyPI as release 0.92.

This revision was uploaded to PyPI as version 0.91.

This revision was released on PyPI as 0.9.

This revision was published on PyPI as release 0.7.

Release v0.6

Version 0.5 of neat-python.