Drop TS test matrix support for TS <5.0

Author: markerikson

.github/workflows/tests.yml

@@ -111,7 +111,7 @@ jobs:
       fail-fast: false
       matrix:
         node: ['20.x']
-        ts: ['4.7', '4.8', '4.9', '5.0', '5.1', '5.2', '5.3', '5.4', '5.5']
+        ts: ['5.0', '5.1', '5.2', '5.3', '5.4', '5.5']
     steps:
       - name: Checkout repo
         uses: actions/checkout@v4