docs(@ngneat/dag): fix the library's readme svg path

[pjlamb12]

fix the path for the image in the library's readme

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] The commit message follows our guidelines: CONTRIBUTING.md#commit
• [ ] Tests for the changes have been added (for bug fixes / features)
• [] Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[x] Documentation content changes
[ ] Other... Please describe:

What is the new behavior?

Fixed the SVG path for the library's README

Does this PR introduce a breaking change?

[ ] Yes
[x] No

[pjlamb12]

@all-contributors add @pjlamb12 for code and docs

[allcontributors[bot]]

@pjlamb12

I've put up a pull request to add @pjlamb12! :tada: