Update micromamba-installation.rst

[KasperThystrup]

Description

In installation instructions for Ubuntu
Changed curl to wget for ubuntu instalation since Curl is not installed by default. Currently it's two commands in a one-liner.

Type of Change

• Bugfix
• Feature / enhancement
• [X ] CI / Documentation
• Maintenance

Checklist

• [X ] My code follows the general style and conventions of the codebase, ensuring consistency
• [ X] I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• [ X] My changes generate no new warnings
• I have run pre-commit run --all locally in the source folder and confirmed that there are no linter errors.
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes