Update Discord links

[huynhicode]

📑 Summary

Base branch set to master.

This PR updates the Discord invite link. Current Discord invite is invalid.

Resolves # 6137

📏 Design Decisions

n/a

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added necessary unit/e2e tests.
• 📓 have added documentation. Make sure MERMAID_RELEASE_VERSION is used for all new features.
• 🦋 If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running pnpm changeset and following the prompts. Changesets that add features should be minor and those that fix bugs should be patch. Please prefix changeset messages with feat:, fix:, or chore:.

[changeset-bot]

⚠️ No Changeset found

Latest commit: fa6f3e5

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 4.49%. Comparing base (becadf0) to head (fa6f3e5).

Files with missing lines	Patch %	Lines
...ermaid/src/docs/.vitepress/components/HomePage.vue	0.00%	1 Missing ⚠️
packages/mermaid/src/docs/.vitepress/config.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #6144      +/-   ##
=========================================
+ Coverage    4.48%   4.49%   +0.01%     
=========================================
  Files         382     382              
  Lines       54027   53904     -123     
  Branches      621     621              
=========================================
  Hits         2425    2425              
+ Misses      51602   51479     -123     

Flag	Coverage Δ
unit	4.49% <0.00%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...ermaid/src/docs/.vitepress/components/HomePage.vue	0.00% <0.00%> (ø)
packages/mermaid/src/docs/.vitepress/config.ts	0.00% <0.00%> (ø)

... and 3 files with indirect coverage changes