Merge pull request cli#4942 from cli/repo-sync-merge-upstream

repo sync: Use the new merge-upstream API if available

Add `auth setup-git` for setting up gh as a git credential helper (cl…

…i#4246)

Adds a new command `gh auth setup-git [<hostname>]` that sets up git to
use the GitHub CLI as a credential helper.

The gist is that it runs these two git commands for each hostname the
user is authenticated with.

```
git config --global --replace-all 'credential.https://github.com.helper' ''
git config --global --add 'credential.https://github.com.helper' '!gh auth git-credential'
```

If a hostname flag is given, it'll setup GH CLI as a credential helper
for only that hostname.

If the user is not authenticated with any git hostnames, or the user is
not authenticated with the hostname given as a flag, it'll print an
error.

Co-authored-by: Mislav Marohnić <[email protected]>

Mark `codespace` a core command

Merge pull request cli#4279 from SiarheiFedartsou/sf-pr-list-head-filter

Add `--head` filter to `gh pr list`

Add helper template functions for rendering tables (cli#3519)

Co-authored-by: Mislav Marohnić <[email protected]>

Merge pull request cli#4087 from cli/graphql-error-fix

Fix unmarshalling GraphQL error type

Merge branch 'trunk' into revert-3926-update-goreleaser-20210630

Fix goreleaser config for linux packages

Merge pull request cli#3924 from cli/rest-org-repo-bug

fix repo create in org with license/ignore

pin goreleaser version