update readme

[yanksyoon]

Applicable spec:

Overview

Updates README.md to conform to latest standards.

Rationale

Juju Events Changes

Module Changes

Library Changes

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation is generated using src-docs
• The documentation for charmhub is updated.
• The PR is tagged with appropriate label (urgent, trivial, complex)

[erinecon]

Thanks for updating the README! It looks great, just one comment from me :)

[erinecon]

Thanks for updating the README!

[github-actions]

Lint checks failed for ffe7766

```

tests/integration/conftest.py:90: error: Incompatible types in assignment (expression has type "Type | None", variable has type "MachineStatus") [assignment]
Found 1 error in 1 file (checked 20 source files)

[github-actions]

Test coverage for ffe7766

Name               Stmts   Miss Branch BrPart  Cover   Missing
--------------------------------------------------------------
src/actions.py        22      0      2      0   100%
src/charm.py          62      0      6      0   100%
src/ssh_debug.py      27      0      4      0   100%
src/state.py          45      0      6      0   100%
src/tmate.py         136      0     12      0   100%
--------------------------------------------------------------
TOTAL                292      0     30      0   100%

Static code analysis report

Run started:2025-01-14 07:07:42.506756

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 1677
  Total lines skipped (#nosec): 9
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 0

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):

[Thanhphan1147]

Hi @yanksyoon, it seems like there's a lint issue, can you take a look? Thanks!