fix deploy to GitHub
Previous change to gitlab-ci.yml moved setting of Gitlab ssh key to global before_script.
This together with the fact that we used `echo >>` instead of `echo >` to write to `id_rsa_base64` file caused wrong key to be used while pushing to GitHub.
Therefore:
- don't run default before_script before push_master_to_github job
- replace echo >> with echo > to avoid mistakes in the future
See merge request !82
Gitlab CI will cache build directory per branch and per build step. Also it doesn't try to update submodules.
We have to do this manually because otherwise we end up with old version of submodule in cached directory.
This change adds gitlab CI support. It tests if latest master of esp-idf-template can be built with the commit of ESP-IDF in question. Currently it's a bit lax because both SDK_PATH and IDF_PATH are defined.
This change also changes components/esp32/lib submodule to point to Github over HTTPS instead of SSH, because CI server might not have its SSH keys uploaded to Github.
