chore(deps): update actions/checkout action to v6 (#14952)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/audit.yml

@@ -17,7 +17,7 @@ jobs:
     if: github.repository == 'sveltejs/kit'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
   pkg-pr-new:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:
@@ -34,7 +34,7 @@ jobs:
   lint-all:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:
@@ -67,7 +67,7 @@ jobs:
       KIT_E2E_BROWSER: ${{matrix.e2e-browser}}
     steps:
       - run: git config --global core.autocrlf false
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:
@@ -127,7 +127,7 @@ jobs:
       KIT_E2E_BROWSER: ${{matrix.e2e-browser}}
     steps:
       - run: git config --global core.autocrlf false
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:
@@ -161,7 +161,7 @@ jobs:
           - mode: 'build'
     steps:
       - run: git config --global core.autocrlf false
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:
@@ -195,7 +195,7 @@ jobs:
           - mode: 'build'
     steps:
       - run: git config --global core.autocrlf false
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:
@@ -224,7 +224,7 @@ jobs:
       matrix:
         node-version: [18, 20, 22, 24]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: pnpm/[email protected]
       - uses: actions/setup-node@v6
         with:

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           # This makes Actions fetch all Git history so that Changesets can generate changelogs with the correct commits
           fetch-depth: 0