fixed capitalization on ecosystem.rst
Fixed capitalization on doc/source/ecosystem.rst

Thanks but `pandas` is intentionally lowercase and was recently changed in https://github.com/pandas-dev/pandas/pull/36845

If further interested in contributing, please check out issues labeled with `good first issue` Where do you think i got it from?
 #32550
./scripts/validate_rst_title_capitalization.py

doc/source/ecosystem.rst:83:Heading capitalization formatted incorrectly. Looks like the `./scripts/validate_rst_title_capitalization.py` has not been modified to ignore capitalization of `pandas`. Would you like to submit a PR to modify that script? Just to make sure,
both Pandas and pandas is fine? It should always be referenced as lowercase `pandas`