update eventsource to 2.6.1 to fix pom/manifest problem

Author: eli-darkly

build.gradle

@@ -74,7 +74,7 @@ ext.versions = [
  "jackson": "2.11.2", 
  "launchdarklyJavaSdkCommon": "1.3.0",
  "okhttp": "4.8.1", // specify this for the SDK build instead of relying on the transitive dependency from okhttp-eventsource
- "okhttpEventsource": "2.6.0",
+ "okhttpEventsource": "2.6.1",
  "slf4j": "1.7.21",
  "snakeyaml": "1.26",
  "jedis": "2.9.0"