Update taiki-e/install-action digest to 638d0bf

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@9bef7e9c3d7c7aa986ef19933b0722880ae377e0 # v2
+        uses: taiki-e/install-action@638d0bf357cd5e20410163cdf70545caa82bfa5f # v2
         with:
           tool: cargo-readme
       - name: Run cargo readme