ci: update GitHub Actions to latest versions

Author: johannschopplich

.github/workflows/ci.yml

@@ -13,10 +13,10 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 1
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v6
       - uses: actions/setup-node@v6
         with:
           node-version: 24

.github/workflows/release.yml

@@ -13,10 +13,10 @@ jobs:
   release:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@v6
       - uses: actions/setup-node@v6
         with:
           node-version: 24