chore(deps): update dependency org.bitcoinj:bitcoinj-core to v0.15.8 (#116)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

build.gradle

@@ -41,7 +41,7 @@ publishing {
 
 
 dependencies {
-    compile group: 'org.bitcoinj', name: 'bitcoinj-core', version: '0.15.6'
+    compile group: 'org.bitcoinj', name: 'bitcoinj-core', version: '0.15.8'
     compile group: 'com.google.code.gson', name: 'gson', version: '2.8.6'
     compile 'com.google.guava:guava:28.2-jre'