Update taiki-e/install-action digest to be7c31b (#250)

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@5e434d46449f862cf1aad510c0b87f51110e7334 # v2
+        uses: taiki-e/install-action@be7c31b6745feec79dec5eb79178466c0670bb2d # v2
         with:
           tool: cargo-readme
       - name: Run cargo readme