Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/action.yml

@@ -15,7 +15,7 @@ jobs:
       actions: write
     steps:
       # checkout this repository
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       # prevent GitHub from suspending cronjob
       - uses: liskin/gh-workflow-keepalive@v1
 
@@ -44,7 +44,7 @@ jobs:
           armbian_release:            "${{ matrix.os }}"                     # userspace: jammy, bookworm, trixie, etc.
           armbian_board:              "${{ matrix.board }}"                  # board build target
           # optional
-          armbian_branch:             "sdk"
+          armbian_branch:             "main"
           armbian_ui:                 "minimal"
           armbian_extensions:         "docker-ce,sdk${{ matrix.extension }}" # enable extensions
           armbian_release_tittle:     "Armbian SDK"                          # release tittle

README.md

@@ -15,7 +15,7 @@
 
 - [x] can be made daily / weekly
 - [x] preinstalled Docker
-- [ ] automated login into user `armbian`
+- [x] automated login into user `armbian`
 - [ ] pre-loaded with latest build script
 - [ ] contains all kernel caches