Release notes for sbmlsim 0.7.1

A patch release of the fixes which 0.7.0 surfaced: the page of the SBML Test Suite in the documentation was replaced by the report it links, the release workflow could not build the submission it attaches, and a file which is not part of the library was published with the sources.

Fixes

• the documentation of the SBML Test Suite is a page again. zensical renders docs/testsuite.md into site/testsuite/index.html and the documentation workflow wrote the interactive report to site/testsuite, so the report replaced the page which describes it: SBML Test Suite served the report without the theme, without the navigation and without the search of the documentation, and the page itself was unreachable. The report is written to site/testsuite/report now and the page links it there, i.e. it is at SBML Test Suite / report. The link of a page is resolved against its source, which is why it carries the testsuite/ of the page itself; tests/testsuite/test_report_path.py pins the two paths against each other, since a report at the address of its documentation renders perfectly well and only the page is missing
• the release workflow builds the submission it attaches. The extension of libroadrunner links against libpython, which the standalone interpreters do not put on the library search path, so the test and the sbml test suite jobs install python<version>-dev first. The release job did not, although the submission it writes imports roadrunner, and it died with ImportError: libpython3.14.so.1.0 on the tag of 0.7.0, after the package was published and before the GitHub release was created. The archive of the submission is an attachment and is continue-on-error now, so a failure to produce it costs the release its attachment and not its notes
• src/roadmap.md is not part of the repository. Personal notes next to the sources were committed by accident and are part of the sdist of 0.7.0 on PyPI, which cannot be changed; the wheel never carried them, since it is built from src/sbmlsim. The file is out of the repository and .gitignore keeps it out