chore(deps): pin dependency deno to 2.5.6

Author: renovate[bot]

.github/workflows/publish-server.yaml

@@ -24,7 +24,7 @@ jobs:
       - name: Install Deno
         uses: denoland/setup-deno@v2
         with:
-          deno-version: v2.x
+          deno-version: 2.5.6
       # run any `bun` or `bunx` command
       - run: bun install
       - run: bun test

.github/workflows/test.yaml

@@ -16,7 +16,7 @@ jobs:
       - name: Install Deno
         uses: denoland/setup-deno@v2
         with:
-          deno-version: v2.x
+          deno-version: 2.5.6
       # run any `bun` or `bunx` command
       - run: bun install
       - run: cd server && bun test