Update doc output folder to always use the name last-doc (gitlab pages job).

It makes easier to access the last API documentation, always the same url.

.gitlab-ci.yml

@@ -215,8 +215,8 @@ pages:
        - if [[ ! -d 'build' ]]; then  mkdir build;fi; cd build
        - 'cmake -DBUILD_WRAPPER_PYTHON=ON -DBUILD_WRAPPER_MATLAB=ON -DBUILD_DOCUMENTATION=ON -DCMAKE_INSTALL_PREFIX=/opt/local/faust -DCPACK_PACKAGE_FILE_NAME=faust-$CI_COMMIT_TAG -DCPACK_PACKAGE_VERSION=$CI_COMMIT_TAG -DEXCLUDE_FAUST_LIB_INSTALL=ON  -DINCLUDE_ALL_SYS_INSTALL_INSTRUCS=ON ..'
        - make doc
-       - mkdir -p ../public/doc-$CI_COMMIT_TAG
-       - cp -Rf doc/html ../public/doc-$CI_COMMIT_TAG/
+       - mkdir -p ../public/last-doc
+       - cp -Rf doc/html ../public/last-doc/
     artifacts:
        paths:
            - public/