Update requirements.txt to 1.12.1 from 1.4.0 as 1.4.0 does not exist anymore.

[abhi1992]

[ajsb85]

ERROR: Could not find a version that satisfies the requirement torch==1.4.0 (from versions: 1.13.0, 1.13.1, 2.0.0, 2.0.1)
ERROR: No matching distribution found for torch==1.4.0

[kopyl]

@ajsb85 same