Update janus requirement from <0.7,>=0.6.2 to >=0.6.2,<0.8 (#1529)

Updates the requirements on [janus](https://github.com/aio-libs/janus) to permit the latest version.
- [Release notes](https://github.com/aio-libs/janus/releases)
- [Changelog](https://github.com/aio-libs/janus/blob/master/CHANGES.rst)
- [Commits](https://github.com/aio-libs/janus/compare/v0.6.2...v0.7.0)

---
updated-dependencies:
- dependency-name: janus
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

setup.py

@@ -52,7 +52,7 @@ setup(
         "pluggy>=0.13,<1.1",
         "uvicorn~=0.11",
         "aiofiles>=0.4,<0.9",
-        "janus>=0.6.2,<0.7",
+        "janus>=0.6.2,<0.8",
         "asgi-csrf>=0.9",
         "PyYAML>=5.3,<7.0",
         "mergedeep>=1.1.1,<1.4.0",