Update plotly requirement from <6.0.0 to <7.0.0

Updates the requirements on [plotly](https://github.com/plotly/plotly.py) to permit the latest version.
- [Release notes](https://github.com/plotly/plotly.py/releases)
- [Changelog](https://github.com/plotly/plotly.py/blob/master/CHANGELOG.md)
- [Commits](plotly/plotly.py@jupyterlab-plotly-v1.0.0-alpha.3...v6.0.0)

---
updated-dependencies:
- dependency-name: plotly
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

pyproject.toml

@@ -47,7 +47,7 @@ dev = [
 charts = [
   'darkdetect',   # Detecting dark mode
   'pandas',       # Displaying tables in juptyer notebooks
-  'plotly<6.0.0', # Interactive plots. 0.6.0 => Empty charts in Jupyter notebooks ...
+  'plotly<7.0.0', # Interactive plots. 0.6.0 => Empty charts in Jupyter notebooks ...
   'py3Dmol',      # Visualisation of crystal structures
 ]
 docs = [