Bug 1684568 [wpt PR 27020] - Update typed-ast to 1.4.2, a=testonly

Automatic update from web-platform-tests
Update typed-ast from 1.4.1 to 1.4.2 (#27020)

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wpt-commits: 88cc8019f0b1f1ae3d7c663a8bd3d7e284902ce3
wpt-pr: 27020

testing/web-platform/tests/tools/requirements_mypy.txt

@@ -1,3 +1,3 @@
 mypy==0.790
 mypy-extensions==0.4.3
-typed-ast==1.4.1
+typed-ast==1.4.2