Bump braveVersion from 5.13.7 to 5.13.8 (#2141)

Bumps `braveVersion` from 5.13.7 to 5.13.8.

Updates `brave-instrumentation-http` from 5.13.7 to 5.13.8

Updates `brave-instrumentation-http-tests` from 5.13.7 to 5.13.8

---
updated-dependencies:
- dependency-name: io.zipkin.brave:brave-instrumentation-http
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: io.zipkin.brave:brave-instrumentation-http-tests
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle

@@ -86,7 +86,7 @@ ext {
 	//Metrics
 	micrometerVersion = '1.5.0' //optional baseline: technically could work with 1.2.x, should work with any 1.3.x
 
-	braveVersion = '5.13.7'
+	braveVersion = '5.13.8'
 
 	jsr305Version = '3.0.2'