Remove repo.spring.io maven repo dependency (hyperledger#1827) (hyper…

…ledger#1828)

According to spring's notification @ https://spring.io/blog/2020/10/29/notice-of-permissions-changes-to-repo-spring-io-fall-and-winter-2020, starting january 21, 2020 repo.spring.io doesnot allow anonymous download of 3rd-party Maven Central artifacts. They suggest all their releases are available at maven central.

Add reference to the splunk repo as mentioned in https://dev.splunk.com/enterprise/docs/devtools/java/logging-java/getstartedloggingjava/installloggingjava/

Signed-off-by: Saravana Perumal Shanmugam <perusworld@linux.com>

build.gradle

@@ -125,7 +125,7 @@ allprojects {
     mavenLocal()
     maven { url "https://hyperledger-org.bintray.com/besu-repo" }
     maven { url "https://consensys.bintray.com/pegasys-repo" }
-    maven { url "https://repo.spring.io/libs-release" }
+    maven { url "https://splunk.jfrog.io/splunk/ext-releases-local" }
     maven { url "https://dl.bintray.com/open-telemetry/maven" }
   }