Update sleeper requirement from ~=1.6.0 to ~=2.0.0

Updates the requirements on [sleeper](https://github.com/joeyagreco/sleeper) to permit the latest version.
- [Release notes](https://github.com/joeyagreco/sleeper/releases)
- [Changelog](https://github.com/joeyagreco/sleeper/blob/main/CHANGELOG.md)
- [Commits](joeyagreco/sleeper@v1.6.0...v2.0.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -4,5 +4,5 @@ numpy~=1.24.4
 openpyxl~=3.1.2
 pymfl~=1.0.2
 setuptools~=66.1.1
-sleeper~=1.6.0
+sleeper~=2.0.0
 yahoofantasy~=1.4.2