build(deps-dev): update coverage[toml] requirement (#678)

Updates the requirements on [coverage[toml]](https://github.com/nedbat/coveragepy) to permit the latest version.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@6.0...7.3.0)

---
updated-dependencies:
- dependency-name: coverage[toml]
  dependency-type: direct:production
...

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pyproject.toml

@@ -52,7 +52,7 @@ docs = [
   "furo>=2023.3.27",
 ]
 test = [
-  "coverage[toml]>=6,<7",
+  "coverage[toml]>=6,<8",
   "pytest>=7,<8",
   "pytest-xdist>=2,<3",
   "pytest-mock>=3,<4",