docs(readme): use absolute URLs for logo and contributing link

Relative paths broke on npmjs.com package page (logo SVGs 404,
CONTRIBUTING.md link points to npm tarball root). Absolute URLs
render correctly on both GitHub and npm.

Author: Chemaclass

README.md

@@ -21,8 +21,8 @@
 <br>
 <p align="center">
     <picture>
-        <source media="(prefers-color-scheme: dark)" srcset="docs/public/logo-name-dark.svg">
-        <img alt="bashunit" src="docs/public/logo-name.svg" width="400">
+        <source media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/TypedDevs/bashunit/main/docs/public/logo-name-dark.svg">
+        <img alt="bashunit" src="https://raw.githubusercontent.com/TypedDevs/bashunit/main/docs/public/logo-name.svg" width="400">
     </picture>
 </p>
 
@@ -50,4 +50,4 @@ bashunit requires **Bash 3.0** or newer.
 You are welcome to contribute reporting issues, sharing ideas,
 or with your pull requests.
 
-Make sure to read our [contribution guide](.github/CONTRIBUTING.md) where you will find, among other things, how to set up your environment with the various tools we use to develop this framework.
+Make sure to read our [contribution guide](https://github.com/TypedDevs/bashunit/blob/main/.github/CONTRIBUTING.md) where you will find, among other things, how to set up your environment with the various tools we use to develop this framework.