Cleanups of build including upgrade of Brave (#1530)

In efforts to dig deep into benchmarks, I noticed we were a bit out of
date on Brave. Then, noticed some other artifacts could be bumped
safely. Finally, a find/replace on http/https was over zealous and
tripped up XML.

One change to test expectations and Brave is explained here:
https://github.com/openzipkin/brave/blob/master/instrumentation/RATIONALE.md#calling-spanfinish-while-the-context-is-in-scope

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/feign/TracingFeignClientTests.java

@@ -89,7 +89,7 @@ public class TracingFeignClientTests {
 		}
 
 		then(this.reporter.getSpans().get(0)).extracting("kind.ordinal")
-				.contains(Span.Kind.CLIENT.ordinal());
+				.isEqualTo(Span.Kind.CLIENT.ordinal());
 	}
 
 	@Test
@@ -113,7 +113,7 @@ public class TracingFeignClientTests {
 		}
 
 		then(this.reporter.getSpans().get(0)).extracting("kind.ordinal")
-				.contains(Span.Kind.CLIENT.ordinal());
+				.isEqualTo(Span.Kind.CLIENT.ordinal());
 		then(this.reporter.getSpans().get(0).tags()).containsEntry("error",
 				"exception has occurred");
 	}