docs: fix redirecting urls in markdown files

[sakethpanuganti]

fix: normalize and repair broken markdown URLs

• Upgrade HTTP links to HTTPS across all docs
• Replace redirecting badge and guidance URLs with canonical targets
• Migrate GitHub links from master to main branch
• Update external service URLs (Travis CI, Maven Central, ASM, CERT)

[cowtowncoder]

As per Claude review:

---

SECURITY.md CERT link — trailing slash and shaky destination. The new URL is
https://certcc.github.io/confluence/display/Wiki/Coordinated+Vulnerability+Disclosure+Guidance/ — a Confluence-style path served from GitHub Pages, ending in /. It currently returns 200 because it's the redirect target of the old vuls.cert.org URL, but this looks like a mirror that may not be stable long-term.

The canonical CERT/CC guidance now lives at https://www.cert.org/vulnerability-analysis/vul-disclosure.cfm or under CMU SEI.

Worth double-checking with maintainers whether they'd prefer the SEI page; at minimum, the trailing slash on a Confluence-style URL is suspicious.

...

Consider replacing with the SEI CERT/CC page (e.g. https://www.cert.org/vulnerability-analysis/vul-disclosure.cfm or
https://insights.sei.cmu.edu/.../coordinated-vulnerability-disclosure-process/) instead — those are more likely to outlive a GitHub Pages mirror.

[cowtowncoder]

Looks good overall, just one concern wrt SECURITY.md link; when that is resolved, happy to merge!