Update taiki-e/install-action digest to e9e8e03 (#508)

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@fd0f63e180a477d7434580b6d80817978b9ff2b8 # v2
+        uses: taiki-e/install-action@e9e8e031bcd90cdbe8ac6bb1d376f8596e587fbf # v2
         with:
           tool: cargo-readme
       - name: Run cargo readme