docs: Update README.md

Co-authored-by: David Siska <[email protected]>

README.md

@@ -53,7 +53,7 @@ For the most part the package is fairly self-contained Python, however there are
   - Install the package into your local environment. 
     - The process for this will vary depending upon your package manager of choice. We provide here a full Poetry `pyproject.toml` and a `requirements.txt` which is derived from it. These are kept in sync through a check on all pull requests. You can [install Poetry here](https://python-poetry.org/docs/#installation) and get everything ready by running `poetry shell` and `poetry install` (or `poetry install --all-extras` to cover all optional extras too). If installing through pip, as above you should also install `requirements-dev.txt` and optionally `requirements-learning.txt`
  -  Run `make test` which checks all the python environment + vega imports are set up correctly, doesn't run Vega yet.
- -  Run `make test_integration` which checks that everything is set up correctly. Takes about 5 minutes.
+ -  Run `make test_integration` which checks that everything is set up correctly. This should take a bit more than 5 minutes and bit less than 30. 
  -  You're good now.