Skip one caller to show the correct file/line that issued the log

[belimawr]

What does this PR do?

Skip one caller to show the correct file/line that issued the log

Why is it important?

When using logp.NewDevelopmentLogger, logp.NewInMemoryLocal, etc. The returned logger was logging logp/logger.go as the source of the log entry.

How to test locally

1. Create the following test on a project that uses logp, or any other place

func TestLogger(t *testing.T) {
	logger, err := logp.NewDevelopmentLogger("selector")
	if err != nil {
		t.Fatal(err)
	}

	logger.Info("foo bar")
}

2. Run the test.
3. The output must contain the correct file name and line instead of logp/logger.go:213

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works

## Author's Checklist
## Related issues

[elasticmachine]

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• Commit: f5412c8

cc @belimawr