Update README.md

[Sarke]

Incorrect config file location

[wagoodman]

Actually, as written is how dive behaves:

$ dive alpine:latest
Using config file: /home/agoodman/.config/dive/config.yaml
Fetching image... (this can take a while with large images)
...

[Sarke]

@wagoodman No, not the latest release.

After some looking around, it seems this was updated very recently:
https://github.com/wagoodman/dive/pull/152/files#diff-04c6e90faac2675aa89e2176d2eec7d8

However, the latest release, which is v0.6.0 for deb, rpm, and docker hub, doesn't not read ~/.config/dive/config.yaml. So yeah, big waste of time going by the documentation not related to he latest release.

Most people will be on the release, not using the master branch.

[wagoodman]

Good catch. It could be a while before I cut the next release, so updating the doc in the meantime makes sense.