Bump actions/cache from 3 to 4 in /.github/actions/build-vsix (#246)

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/actions/build-vsix/action.yml

@@ -22,7 +22,7 @@ runs:
         python-version: 3.8
 
     - name: Pip cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/pip
         key: ${{ runner.os }}-pip-build-vsix-${{ hashFiles('**/requirements.txt') }}