ci: match the actions/cache pin comment to its exact tag (v5.0.5)

zizmor 1.25.2 fails ref-version-mismatch on every PR since upstream's
moving v5 tag advanced past the pinned commit: 27d5ce7f is tag v5.0.5,
while v5 now points at caa29612. Pin comments must name the exact tag
the hash resolves to.

Change-Id: Ie11f20be5af490177f782009fb876d067e41a41e
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Signed-off-by: Thomas Kosiewski <tk@coder.com>

Author: ThomasK33

.github/workflows/ci.yml

@@ -55,7 +55,7 @@ jobs:
         run: echo "STORE_PATH=$(pnpm store path --silent)" >> "$GITHUB_ENV"
 
       - name: Cache pnpm store
-        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
         with:
           path: ${{ env.STORE_PATH }}
           key: ${{ runner.os }}-node${{ matrix.node }}-pnpm-${{ hashFiles('pnpm-lock.yaml') }}