Could not resolve proxy - git clone

参考：https://stackoverflow.com/questions/50996912/could-not-resolve-proxy-git-clone/51016837

Git has its own proxy.

To reset git proxy:

git config --global https.proxy ""
git config --global http.proxy ""

To reset system proxy:

On Ubuntu, you can set proxy by using

export http_proxy=""
export https_proxy=""

export all_proxy=""

Then run

git clone