Remove deprecated extended_dump option

[airlaser]

Resolves #265

Extended dump was made obsolete by the change to GraphQL and is no longer useful. The variable is not used outside of being assigned.

[codecov]

Codecov Report

Merging #266 into master will decrease coverage by 0.43%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #266      +/-   ##
==========================================
- Coverage   80.08%   79.64%   -0.44%     
==========================================
  Files          16       16              
  Lines         959      958       -1     
  Branches      131      131              
==========================================
- Hits          768      763       -5     
- Misses        151      158       +7     
+ Partials       40       37       -3

Impacted Files	Coverage Δ
instalooter/cli/constants.py	83.33% <ø> (ø)	⬆️
instalooter/cli/__init__.py	62.71% <ø> (ø)	⬆️
instalooter/batch.py	81.57% <ø> (ø)	⬆️
instalooter/looters.py	73.45% <ø> (-1.55%)	⬇️

---

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 0001e32...8b4b9a2. Read the comment docs.

[althonos]

Thanks! I'll merge, but this will require a new major release (the fix is a breaking change) so it may take some time before I actually push it.