Make default behaviour to try and read with pandas read_csv

[znicholls]

Pull request

Please confirm that this pull request has done the following:

• Tests added
• Documentation added (where applicable)
• Example added (either to an existing notebook or as a new notebook, where applicable) (N/A)
• Description in CHANGELOG.rst added

Adding to CHANGELOG.rst

Please add a single line in the changelog notes similar to one of the following:

- (`#XX <https://github.com/openscm/scmdata/pull/XX>`_) Added feature which does something
- (`#XX <https://github.com/openscm/scmdata/pull/XX>`_) Fixed bug identified in (`#YY <https://github.com/openscm/scmdata/issues/YY>`_)

[codecov]

Codecov Report

Merging #100 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #100   +/-   ##
=======================================
  Coverage   94.65%   94.66%           
=======================================
  Files          15       15           
  Lines        1647     1649    +2     
  Branches      366      366           
=======================================
+ Hits         1559     1561    +2     
  Misses         60       60           
  Partials       28       28           

Impacted Files	Coverage Δ
src/scmdata/run.py	93.54% <100.00%> (+0.02%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 75e51bf...4bf82fe. Read the comment docs.

[lewisjared]

Brilliant