Fix capitalization in README.md

[aroramrinaal]

I noticed a minor capitalization issue in the README.md file. This PR aims to fix the capitalization for better readability and adherence to conventional writing style.

Changes Made:

• Capitalized the first letter of each sentence in the following sections:
  • Without relying on pre-specified invariances to hand-crafted data transformations, which tend to be biased for particular downstream tasks.
  • And without having the model fill in pixel-level details, which tend to result in learning less semantically meaningful representations.