Bump actions/cache from 5 to 6 (#686)

Author: dependabot[bot]

.github/workflows/docs.yml

@@ -52,7 +52,7 @@ jobs:
         run: git fetch origin 'refs/tags/*:refs/tags/*'
 
       - name: Setup caching for conda packages
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: ~/conda_pkgs_dir
           key: conda-${{ env.PYTHON }}-${{ hashFiles('.github/environment.yml') }}

.github/workflows/test.yml

@@ -106,7 +106,7 @@ jobs:
           echo "dir="$(pip cache dir) >> $GITHUB_OUTPUT
 
       - name: Setup caching for pip packages
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: ${{ steps.pip-cache.outputs.dir }}
           key: ${{ runner.os }}-pip-${{ hashFiles('requirements-full.txt') }}
@@ -189,7 +189,7 @@ jobs:
         run: echo "dir=$(pip cache dir)" >> $GITHUB_OUTPUT
 
       - name: Setup caching for pip packages
-        uses: actions/cache@v5
+        uses: actions/cache@v6
         with:
           path: ${{ steps.pip-cache.outputs.dir }}
           key: ${{ runner.os }}-pip-coverage