Update taiki-e/install-action digest to c5b1b6f (#378)

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@1c7b1d35fcc8f6525be0cbdacbf5977079a3f94c # v2
+        uses: taiki-e/install-action@c5b1b6f479c32f356cc6f4ba672a47f63853b13b # v2
         with:
           tool: cargo-readme
       - name: Run cargo readme