specify upstream when pushing a branch for the first time

Update README.md

Vendor: Updated dependencies

 * Updated go.mod
 * Updated go.sum
 * Updated vendor packages

Signed-off-by: Glenn Vriesman <[email protected]>

rm go.sum && go mod vendor

support clicking through to commit files panel

fix tests

\jesseduffield#480 Close popup panels before switching to a side view

Reusing the `onNewPopupPanel` function to close existing popup panels
(if any) before switching to a new side view. Alse closing any
confirmation prompt.

update go.sum

Merge branch 'master' of https://github.com/jesseduffield/lazygit

Support opening lazygit in a submodule