Bugfix for `update_prices.py` and updated dev dependencies

[dot-agi]

• Fixes the exception ValueError: Unknown format code 'f' for object of type 'str' This is encountered when running the script and is caused by the first row with the sample_spec value which is a string.

• Added tabulate and pandas dependencies These dependencies are added to the dev section so that one can run this script if the packages are installed from the repo.