Bump fortran-lang/setup-fpm from 5 to 6

Bumps [fortran-lang/setup-fpm](https://github.com/fortran-lang/setup-fpm) from 5 to 6.
- [Release notes](https://github.com/fortran-lang/setup-fpm/releases)
- [Commits](fortran-lang/setup-fpm@v5...v6)

---
updated-dependencies:
- dependency-name: fortran-lang/setup-fpm
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/CI.yml

@@ -55,7 +55,7 @@ jobs:
 
     # Phase 1: Bootstrap fpm with existing version
     - name: Install fpm
-      uses: fortran-lang/setup-fpm@v5
+      uses: fortran-lang/setup-fpm@v6
       with:
         fpm-version: 'v0.8.0'
 

.github/workflows/meta.yml

@@ -220,7 +220,7 @@ jobs:
 
     # Phase 1: Bootstrap fpm with existing version
     - name: Install fpm
-      uses: fortran-lang/setup-fpm@v5
+      uses: fortran-lang/setup-fpm@v6
       with:
         fpm-version: 'v0.8.0'
 

.github/workflows/release.yml

@@ -67,7 +67,7 @@ jobs:
         patch -p1 < ./ci/single-file.patch
 
     - name: Install fpm
-      uses: fortran-lang/setup-fpm@v5
+      uses: fortran-lang/setup-fpm@v6
       with:
         fpm-version: 'v0.8.0'