Added conda installation instructions similar to other dev branches
In the README file, the installation instructions with conda were missing as compared to other dev branches, https://github.com/aerospaceresearch/DirectDemod/tree/Vinay_dev and https://github.com/aerospaceresearch/DirectDemod/tree/Vladyslav_dev. I have modified the conda env instruction, of installing with an environment.yml file, and have suggested to create an own environment, and installing using pip from requirement.txt file.
Also updated installing the requirements.txt using pip to conda, because earlier was mixing dependencies and breaking the system. (This error might not be faced by everybody, but still using conda as it manages packages better than pip)
Depreciation Warning Added