Fix qv circuits bug (#21)

* quantum_volume.py - reverted simulation circuits to untranspiled and removed "sorted_qc_list_indices" from dataset when layout is "fixed"

* updated example_quantum_volume.ipynb with outputs displayed

* readout_mitigation.py - modified suppression of mthree logging messages by changing the logger level; cleaner outputs

* updated CHANGELOG.rst

* linting (removed unused sys package due to change to logging suppression)

---------

Co-authored-by: Pedro Figueroa <pedro.romero@meetiqm.com>

CHANGELOG.rst

@@ -2,6 +2,10 @@
 Changelog
 =========
 
+Version 2.3
+===========
+* Reverted QV simulation circuits to untranspiled ones (fixes bug giving all HOPs equal to zero).
+
 Version 2.2
 ===========
 * Added Clifford RB example notebook to docs. `#20 <https://github.com/iqm-finland/iqm-benchmarks/pull/20>`_