Upgradle gradle to 6.5 (DataDog/dd-trace-java#1589)

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.4.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

instrumentation/okhttp/okhttp-3.0/okhttp-3.0.gradle

@@ -33,7 +33,6 @@ dependencies {
   testCompile(project(':testing')) {
     exclude module: 'okhttp'
   }
-  testCompile project(':instrumentation:java-concurrent')
   testCompile group: 'com.squareup.okhttp3', name: 'okhttp', version: '3.0.0'
 
   // 4.x.x-alpha has been released and it looks like there are lots of incompatible changes