Update the Go version to 1.21.x

[Aisuko]

Description

Other repos were already updated to v1.12.x. So, in order to avoid the non-compatible issues of dependencies' version. We need to upgrade the version soon.

Expected Behavior

Screenshots

Environment:

• OS: [e.g. Ubuntu]
• Browser: [e.g. Chrome, Safari]
• Version: [e.g. 22]
• Device: [e.g. laptop, iPhone 8]

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[Optional] To Reproduce Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

[Optional] Additional Context

Contributor Resources

The meshery.io website uses Jekyll and GitHub Pages. Site content is found under the master branch.

• See the Contributing to Meshery.io Website section of the readme.md and other contributing instructions, too.
• See Meshery site designs in this Figma designfile. Fill-in the Layer5 Community Member Form and join the Layer5 Community Slack for access.

[Aisuko]

Repeat #125