Bump actions/cache from 5 to 6 (#40)

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

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/main.yml

@@ -24,7 +24,7 @@ jobs:
 
     - name: Cache choosenim
       id: cache-choosenim
-      uses: actions/cache@v5
+      uses: actions/cache@v6
       with:
         path: ~/.nimble
         key: nimble-v2-${{ matrix.nim }}-${{ hashFiles('dimscmd.nimble') }}
@@ -60,7 +60,7 @@ jobs:
 
       - name: Cache choosenim
         id: cache-choosenim
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: ~/.nimble
           key: nimble-v2-stable-${{ hashFiles('dimscmd.nimble') }}