fix(lint): re-enable the gosec G402 rule

[Coder-in-a-shell]

Problem

G402: TLS MinVersion too low has been excluded from gosec since #9693. The exclusion was explicitly temporary — the comment says to revert it once golangci-lint moved past v1.50.1, which brought in the gosec v2.13.1 → v2.14.0 fix for the false positive:

  # Temporarily disable this check until the next golang-ci upgrade (greater
  # than v1.50.1) which upgrades gosec from v2.13.1 to v2.14.0. ...
  - linters:
    - gosec
    text: "G402: TLS MinVersion too low"

That upgrade landed long ago. CI runs golangci-lint v1.64.8 (via ghcr.io/linkerd/dev:v50-go, which installs cmd/golangci-lint@latest), so the workaround is dead weight and a real TLS misconfiguration would currently go unreported.

Solution

Delete the exclusion. No code changes were needed.

Validation

Run with golangci-lint v1.64.8 to match the dev image.

1. Baseline on main — clean:

$ golangci-lint run --timeout=15m
(exit 0, no output)

2. With the exclusion removed — still clean, so there are no real G402 violations to fix:

$ golangci-lint run --timeout=15m
(exit 0, no output)

3. Confirmed the rule actually fires rather than the removal being a no-op. Temporarily added:

// pkg/tls/g402_probe.go
func TempProbe() *tls.Config {
	return &tls.Config{MinVersion: tls.VersionTLS10}
}

pkg/tls/g402_probe.go:7:10: G402: TLS MinVersion too low. (gosec)
	return &tls.Config{MinVersion: tls.VersionTLS10}
	        ^

4. Confirmed the exclusion was genuinely suppressing it — restoring the old config and re-running against the same probe reports nothing.

The probe file was removed before committing; the diff is the 8-line config deletion only.

Fixes #9700

Signed-off-by: Sudhir Jaiswal jaiswalsudhir2944@gmail.com