MNT: (deps): Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3...v4)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/docs-conda.yml

@@ -35,7 +35,7 @@ jobs:
       run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
 
     - name: Setup conda caching
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/conda_pkgs_dir
         key: conda-docs-${{ runner.os }}-${{ matrix.python-version}}-${{ hashFiles('ci/*') }}
@@ -64,7 +64,7 @@ jobs:
       run: echo "::set-output name=dir::$(python -c 'import cartopy;print(cartopy.config["data_dir"])')"
 
     - name: Setup mapdata caching
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       env:
         # Increase to reset cache of map data
         CACHE_NUMBER: 0

.github/workflows/docs.yml

@@ -58,7 +58,7 @@ jobs:
       run: echo "::set-output name=dir::$(pip cache dir)"
 
     - name: Setup pip cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ${{ steps.pip-cache.outputs.dir }}
         key: pip-docs-${{ runner.os }}-${{ matrix.python-version }}-${{ hashFiles('ci/*') }}
@@ -85,7 +85,7 @@ jobs:
       run: echo "::set-output name=dir::$(python -c 'import cartopy;print(cartopy.config["data_dir"])')"
 
     - name: Setup mapdata caching
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       env:
         # Increase to reset cache of map data
         CACHE_NUMBER: 0

.github/workflows/tests-conda.yml

@@ -34,7 +34,7 @@ jobs:
       run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
 
     - name: Setup conda caching
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/conda_pkgs_dir
         key: conda-tests-${{ runner.os }}-${{ matrix.python-version}}-${{ hashFiles('ci/*') }}

.github/workflows/tests-pypi.yml

@@ -53,7 +53,7 @@ jobs:
       run: echo "::set-output name=dir::$(pip cache dir)"
 
     - name: Setup caching
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ${{ steps.pip-cache.outputs.dir }}
         key: pip-tests-${{ runner.os }}-${{ matrix.python-version }}-${{ hashFiles('ci/*') }}