update pennylane.md with new pennylane version

[TheKharleeci]

Proposed changes

• update pennylane versions
• edit commands to use the default version
• rearrange quantum discipline alphabetically

Checklist before requesting a review

• [x] I have followed the instructions in the Contributing and Styleguide documents.
• [x] My pull request passes all tests.
• [x] I have included a link to the appropriate preview page.