Added option to using a skipper in the echo otel middleware

[pcairns]

Allow for a skipper (https://github.com/labstack/echo/blob/master/middleware/middleware.go#L15) to be passed into the echo middleware. The use case for this is we would like the ability to bypass tracing for certain routes (eg. health check endpoints).

[linux-foundation-easycla]

The committers are authorized under a signed CLA.

• ✅ pcairns (aea42e9)

[Aneurysm9]

@pcairns I think you may need to rebase this to eliminate commit 366d0ca. All commits must be from users that have signed the CLA.

[codecov]

Codecov Report

Merging #829 (8ac37cc) into main (595663d) will increase coverage by 0.0%.
The diff coverage is 100.0%.

@@          Coverage Diff          @@
##            main    #829   +/-   ##
=====================================
  Coverage   75.4%   75.4%           
=====================================
  Files         69      69           
  Lines       3064    3071    +7     
=====================================
+ Hits        2311    2318    +7     
  Misses       613     613           
  Partials     140     140           

Impacted Files	Coverage Δ
...tation/github.com/labstack/echo/otelecho/config.go	100.0% <100.0%> (ø)
...entation/github.com/labstack/echo/otelecho/echo.go	95.4% <100.0%> (+0.4%)	⬆️

[pcairns]

@Aneurysm9 sorry I've been away on vacation, this should be rebased now

[pellared]

one little comment to make the test(s) more trustworthy

other than that looks great 👍

[pcairns]

I've updated the tests to include a check for the status code