Router: auto HEAD to GET

[aldas]

Proposal for alternative solution to #2944 (#2895) - do not register extra routes. use router internals to fallback from head to get. these extra IF checks do not register as meaningful change when running benchstat, but registering another route along with GET looks like a quick hack.

store benchmarks for this change

go test -run="-" -bench=".*" -count=8 ./... > benchmark_with_head.txt

check out current version

go test -run="-" -bench=".*" -count=8 ./... > benchmark_5_1_0.txt

and compare these two

benchstat benchmark_5_1_0.txt benchmark_with_head.txt 

---

usage:

Create Echo instance with Router that is configured with AutoHandleHEAD = true

			e := echo.NewWithConfig(echo.Config{
				Router: echo.NewRouter(echo.RouterConfig{
					AutoHandleHEAD: true,
				}),
			})

[codecov]

Codecov Report

❌ Patch coverage is 97.29730% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.44%. Comparing base (01b45be) to head (c97f73c).
⚠️ Report is 28 commits behind head on master.

Files with missing lines	Patch %	Lines
response.go	96.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2949      +/-   ##
==========================================
+ Coverage   93.17%   93.44%   +0.26%     
==========================================
  Files          43       43              
  Lines        4501     4712     +211     
==========================================
+ Hits         4194     4403     +209     
+ Misses        189      188       -1     
- Partials      118      121       +3     

☔ View full report in Codecov by Harness.
📢 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.

[atharvaSharma17]

Any updates on this ??