Fix crash when viewing the divergence of a branch which is up to date…

… with its upstream (#3918)

This was introduced by #3838, specifically by commit e675025.

Fixes #3900 and #3917.

Switch to Files panel after popping a stash (#3888)

#### PR Description

I find myself always switching to the Files panel after popping a stash,
100% of the time, so it makes sense that lazygit does this for me. Do it
for apply as well, for consistency.

#### Please check if the PR fulfills these requirements

* [x] Cheatsheets are up-to-date (run `go generate ./...`)
* [x] Code has been formatted (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#code-formatting))
* [x] Tests have been added/updated (see
[here](https://github.com/jesseduffield/lazygit/blob/master/pkg/integration/README.md)
for the integration test guide)
* [ ] Text is internationalised (see
[here](https://github.com/jesseduffield/lazygit/blob/master/CONTRIBUTING.md#internationalisation))
* [ ] If a new UserConfig entry was added, make sure it can be
hot-reloaded (see
[here](https://github.com/jesseduffield/lazygit/blob/master/docs/dev/Codebase_Guide.md#using-userconfig))
* [ ] Docs have been updated if necessary
* [x] You've read through your own file changes for silly mistakes etc

Fix language auto detection (#3744)

- **PR Description**

Fix a regression (introduced with #3649) that broke language
auto-detection. When starting lazygit with the `gui.language` config set
to "auto" (which is the default), lazygit would fail to start if the
LANG environment is set to one of our supported languages.

For example:
```
$ export LANG=nl_NL
$ lazygit
2024/07/13 11:43:03 open translations/nl-NL.json: file does not exist
```

Fixes #3743

README.md: Update Sponsors (#3732)

Automated changes by
[create-pull-request](https://github.com/peter-evans/create-pull-request)
GitHub action

Correctly request force-pushing in a triangular workflow (#3528)

- **PR Description**

Some people push to a different branch (or even remote) than they pull
from. One example is described in #3437. Our logic of when to request a
force push is not appropriate for these workflows: we check the
configured upstream branch for divergence, but that's the one you pull
from. We should instead check the push-to branch for divergence.

Fixes #3437.

Fix container detection (#3412)

- **PR Description**

Running WSL without a container would be treated as native linux,
causing problems at it would then attempt to use `xdg-open`. This was
caused by `isContainer()` always returning true due to some dubious
conditionals. These have been removed.

The env-var check seems to not be used by lazygit, nor any common
containers, and therefore appears to only exist to manually tell lazygit
to behave as if it were inside of a container. This functionality has
been kept, but the env-var has been changed to be all uppercaps as to
comply with the POSIX standard.

Fixes #2757
Bug introduced in 4d78d76

Fix container detection (#3412)

- **PR Description**

Running WSL without a container would be treated as native linux,
causing problems at it would then attempt to use `xdg-open`. This was
caused by `isContainer()` always returning true due to some dubious
conditionals. These have been removed.

The env-var check seems to not be used by lazygit, nor any common
containers, and therefore appears to only exist to manually tell lazygit
to behave as if it were inside of a container. This functionality has
been kept, but the env-var has been changed to be all uppercaps as to
comply with the POSIX standard.

Fixes #2757
Bug introduced in 4d78d76

Updated README.md

Fix opening lazygit in a bare repo with specified worktree (#2902)

Updated README.md