Update taiki-e/install-action digest to 9903ab6 (#252)

Author: nextest-bot

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
       - name: Lint (rustfmt)
         run: cargo xfmt --check
       - name: Install cargo readme
-        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
+        uses: taiki-e/install-action@9903ab6feadaec33945de535fe9d181b91802a55 # v2
         with:
           tool: cargo-readme
       - name: Run cargo readme