Bump actions/cache from 3 to 4 (#1346)

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

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -30,7 +30,7 @@ jobs:
 
     - name: Restore Python ${{ steps.python.outputs.python-version }} virtual environment
       id: cache-venv
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: venv
         key: >-
@@ -94,7 +94,7 @@ jobs:
 
     - name: Restore Python ${{ steps.python.outputs.python-version }} virtual environment
       id: cache-venv
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: venv
         key: >-
@@ -135,7 +135,7 @@ jobs:
 
     - name: Cache PMS Docker image
       id: docker-cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/docker/plexinc
         key: ${{ runner.os }}-docker-pms-${{ steps.docker-digest.outputs.digest }}
@@ -230,7 +230,7 @@ jobs:
 
     - name: Restore Python ${{ steps.python.outputs.python-version }} virtual environment
       id: cache-venv
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: venv
         key: >-