Update taiki-e/install-action digest to 8cd2ac2 (#393)

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@537c30d2b45cc3aa3fb35e2bbcfb61ef93fd6f02 # v2
+        uses: taiki-e/install-action@8cd2ac21dc357ca7dd807fe294d11e9ef84f60ec # v2
         with:
           tool: cargo-readme
       - name: Run cargo readme