Bump fairscale from 0.4.2 to 0.4.3 (#5474)

Bumps [fairscale]() from 0.4.2 to 0.4.3.

---
updated-dependencies:
- dependency-name: fairscale
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Akshita Bhagia <akshita23bhagia@gmail.com>

setup.py

@@ -53,7 +53,7 @@
         "torch>=1.6.0,<1.11.0",
         "torchvision>=0.8.1,<0.12.0",
         "cached-path>=0.3.4,<0.4.0",
-        "fairscale==0.4.2",
+        "fairscale==0.4.3",
         "jsonnet>=0.10.0 ; sys.platform != 'win32'",
         "overrides==3.1.0",
         "nltk",