Add runbook for local port forwarding with OpenAPI3

[k1LoW]

ref: #532

[github-actions]

Code Metrics Report

	main (f103866)	#535 (4ad8925)	+/-
Coverage	69.0%	69.0%	0.0%
Code to Test Ratio	1:0.6	1:0.6	+0.0
Test Execution Time	2m48s	3m55s	+1m7s

Details

  |                     | main (f103866) | #535 (4ad8925) |  +/-  |
  |---------------------|----------------|----------------|-------|
  | Coverage            |          69.0% |          69.0% |  0.0% |
  |   Files             |             47 |             47 |     0 |
  |   Lines             |           5011 |           5011 |     0 |
  |   Covered           |           3457 |           3457 |     0 |
+ | Code to Test Ratio  |          1:0.6 |          1:0.6 |  +0.0 |
  |   Code              |          10020 |          10020 |     0 |
+ |   Test              |           6496 |           6502 |    +6 |
- | Test Execution Time |          2m48s |          3m55s | +1m7s |

Code coverage of files in pull request scope (58.2% → 58.2%)

Files	Coverage	+/-
book.go	67.6%	0.0%
option.go	62.8%	0.0%
ssh.go	59.3%	0.0%
testutil/container.go	0.0%	0.0%

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Reported by octocov