Fixed version number discrepancy

[suwakei]

Fix mismatch between Go version check logic and warning message

Problem

There is a mismatch between the Go version check logic and the warning message shown to users:

• Constant: const ginSupportMinGoVer = 21
• Message: "[WARNING] Now Gin requires Go 1.23+\n"

As a result, users running Go 1.21 or 1.22 cannot see the warning, even though the message states that 1.23+ is required.

Cause

The logic in debugPrintWARNINGDefault():

func debugPrintWARNINGDefault() {
	if v, e := getMinVer(runtime.Version()); e == nil && v < ginSupportMinGoVer {
		debugPrint(`[WARNING] Now Gin requires Go 1.23+.

`)

With ginSupportMinGoVer = 21, however, users on Go 1.21 (v = 21) or 1.22 (v = 22) don't trigger the warning (v < 21 is false).

Fix

Update the constant ginSupportMinGoVer to 23 to match the warning message indicating that Go 1.23+ is required.

This ensures users running Go versions below 1.23 will properly receive the warning,
aligning behavior with messaging.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.92%. Comparing base (3dc1cd6) to head (514bdcd).
Report is 143 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4299      +/-   ##
==========================================
- Coverage   99.21%   98.92%   -0.30%     
==========================================
  Files          42       44       +2     
  Lines        3182     3437     +255     
==========================================
+ Hits         3157     3400     +243     
- Misses         17       26       +9     
- Partials        8       11       +3     

Flag	Coverage Δ
	?
--ldflags="-checklinkname=0" -tags sonic	98.85% <ø> (?)
-tags go_json	98.85% <ø> (?)
-tags nomsgpack	98.90% <ø> (?)
go-1.18	?
go-1.19	?
go-1.20	?
go-1.21	?
go-1.23	98.92% <ø> (?)
go-1.24	98.92% <ø> (?)
macos-latest	98.92% <ø> (-0.30%)	⬇️
ubuntu-latest	98.92% <ø> (-0.30%)	⬇️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[suwakei]

We have verified that this change has written tests for all modified code.

The Codecov report also shows that all modified lines are covered.

The -0.30% decrease in overall coverage is likely due to the fact that the base branch is 142 commits older than master and does not affect this fix.

We appreciate your confirmation.