fix: bump TS version in react script CLI fixture to avoid Yarn 2 inst…

…all issue

When Yarn 2 is trying to install and patch TS 3.6 it throws:
➤ YN0013: │ typescript@patch:typescript@npm%3A3.6.5#builtin<compat/typescript>::version=3.6.5&hash=c79188 can't be found in the cache and will be fetched from the disk
➤ YN0001: │ Error: typescript@patch:typescript@npm%3A3.6.5#builtin<compat/typescript>::version=3.6.5&hash=c79188: Cannot apply hunk #5

This is a Yarn 2 related issue, tracked here: yarnpkg/berry#1221

lib/cli/test/fixtures/react_scripts_ts/package.json

@@ -31,6 +31,6 @@
     "react": "^16.10.2",
     "react-dom": "^16.10.2",
     "react-scripts": "3.2.0",
-    "typescript": "3.6.4"
+    "typescript": "3.8.3"
   }
 }