Upgrade coverage to 7.2.7

We received error messages in older version of the coverage so we
upgrade to the latest one, coverage 7.2.7, which still supports Python
3.7.

See this run for more details:
https://github.com/Parquery/icontract/actions/runs/9779072024/job/26997391256?pr=292

setup.py

@@ -57,7 +57,7 @@
             'pylint==2.17.5;python_version>="3.7"',
             "tox>=3.0.0",
             "pydocstyle>=6.3.0,<7",
-            "coverage>=4.5.1,<5",
+            "coverage>=7.2.7,<8",
             "docutils>=0.14,<1",
             "pygments>=2.2.0,<3",
             "dpcontracts==0.6.0",