Bump actions/checkout from 1 to 6 (#583)

* Bump actions/checkout from 1 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 1 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v1...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>

* 32bit-ci.yml: Stick with old actions/checkout

...for compatibility.

As suggested by @konsumlamm.

Co-authored-by: konsumlamm <44230978+konsumlamm@users.noreply.github.com>

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Simon Jakobi <simon.jakobi@gmail.com>
Co-authored-by: konsumlamm <44230978+konsumlamm@users.noreply.github.com>

Author: 3 people

.github/workflows/haskell-ci.yml

@@ -165,7 +165,7 @@ jobs:
           chmod a+x $HOME/.cabal/bin/cabal-plan
           cabal-plan --version
       - name: checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           path: source
       - name: initial cabal.project for sdist

.github/workflows/mhs-ci.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
 
     - name: checkout mhs repo
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
         repository: augustss/MicroHs
         ref: v0.14.23.1
@@ -23,7 +23,7 @@ jobs:
         make minstall
 
     - name: checkout unordered-containers repo
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
         path: unordered-containers
     - name: compile and install unordered-containers package