docs: update pip install instructions

because https://snarky.ca/why-you-should-use-python-m-pip/

Author: zkoppert

README.md

@@ -52,7 +52,7 @@ jobs:
 1. Fill out the `.env` file with the exact _topic_ name you are searching for
 1. Fill out the `.env` file with the exact _organization_ that you want to search in
 1. (Optional) Fill out the `.env` file with the exact _URL_ of the GitHub Enterprise that you want to search in. Keep empty if you want to search in the  public `github.com`.
-1. `pip install -r requirements.txt`
+1. `python -m pip install -r requirements.txt`
 1. Run `python3 ./crawler.py`, which will create a `repos.json` file containing the relevant metadata for the GitHub repos for the given _topic_
 1. Copy `repos.json` to your instance of the [SAP-InnerSource-Portal][SAP-InnerSource-Portal] and launch the portal as outlined in their installation instructions