Update http(s) proxy settings for git

update-git-proxy-config.sh

# read in username and password for system http(s) proxy settings
read -s -p "Username: " USERNAME; echo ''
read -s -p "Password: " PASSWORD; echo ''
read -s -p "HTTP(S) Proxy (host:port): " HTTP_PROXY_HOST_PORT; echo ''

export {http_proxy,https_proxy}="http://$USERNAME:$PASSWORD@$HTTP_PROXY_HOST_PORT"

# update http(s) proxy settings for git
git config --global http.proxy $http_proxy
git config --global https.proxy $https_proxy
git config --global http.sslVerify false
git config --global https.sslVerify false

# you may want to limit access to this config from now on
chmod 600 ~/.gitconfig

# and probably unset the env variables
unset USERNAME PASSWORD