Add the ability to trip the circuit breaker based on returned status code

[ryanjbaxter]

In some cases you might want to trip a circuit breaker based on the status code returned from the downstream service. This provides a way to set a list of status codes to do this.

[codecov]

Codecov Report

Merging #1836 into 2.2.x will increase coverage by 0.07%.
The diff coverage is 88.88%.

@@             Coverage Diff              @@
##              2.2.x    #1836      +/-   ##
============================================
+ Coverage     74.49%   74.57%   +0.07%     
- Complexity     1280     1283       +3     
============================================
  Files           168      168              
  Lines          5473     5494      +21     
  Branches        420      421       +1     
============================================
+ Hits           4077     4097      +20     
- Misses         1179     1180       +1     
  Partials        217      217              

Impacted Files	Coverage Δ	Complexity Δ
...actory/SpringCloudCircuitBreakerFilterFactory.java	92.42% <85.00%> (-3.33%)	8.00 <1.00> (+1.00)	⬇️
...eway/filter/factory/RetryGatewayFilterFactory.java	77.71% <100.00%> (-0.50%)	36.00 <1.00> (-1.00)
.../cloud/gateway/support/ServerWebExchangeUtils.java	88.59% <100.00%> (+0.63%)	31.00 <2.00> (+2.00)
...cloud/gateway/filter/NettyWriteResponseFilter.java	80.85% <0.00%> (+4.25%)	16.00% <0.00%> (+1.00%)

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[spencergibb]

One minor change, after that, LGTM