6714 fixes docker build on github ci (#6718)

fixes #6714

release more disk space for docker build on github ci

tested:
https://github.com/Project-MONAI/MONAI/actions/runs/5551644874/jobs/10138058790


### Types of changes
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [ ] Breaking change (fix or new feature that would cause existing
functionality to change).
- [ ] New tests added to cover the changes.
- [ ] Integration tests passed locally by running `./runtests.sh -f -u
--net --coverage`.
- [ ] Quick tests passed locally by running `./runtests.sh --quick
--unittests --disttests`.
- [ ] In-line docstrings updated.
- [ ] Documentation updated, tested `make html` command in the `docs/`
folder.

---------

Signed-off-by: Wenqi Li <[email protected]>

.github/workflows/docker.yml

@@ -62,6 +62,7 @@ jobs:
     - name: docker_build
       shell: bash
       run: |
+        rm -rf /opt/hostedtoolcache
         docker --version
         # get tag info for versioning
         cat _version.py