Update taiki-e/install-action digest to 6f69ec9 (#349)

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@5597bc27da443ba8bf9a3bc4e5459ea59177de42 # v2
+        uses: taiki-e/install-action@6f69ec9970ed0c500b1b76d648e05c4c7e0e5671 # v2
         with:
           tool: cargo-readme
       - name: Run cargo readme