#14 Fix jacoco xml report destination in README

[colddew]

hi, i have used gradle-5.1 to execute codeCoverageReport command, it throw exception as follow, and i solve this problem when i change xml.destination "${buildDir}/reports/jacoco/report.xml" to xml.destination file("${buildDir}/reports/jacoco/report.xml")

➜  micro-service-gradle git:(master) gradle clean test codeCoverageReport        
Starting a Gradle Daemon (subsequent builds will be faster)

FAILURE: Build failed with an exception.

* Where:
Build file '/Users/anmy/workspace/workspace-new/micro-service-lab/micro-service-gradle/build.gradle' line: 74

* What went wrong:
A problem occurred evaluating root project 'micro-service-gradle'.
> Could not find method destination() for arguments [/Users/anmy/workspace/workspace-new/micro-service-lab/micro-service-gradle/build/reports/jacoco/report.xml] on Report xml of type org.gradle.api.reporting.internal.TaskGeneratedSingleFileReport.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 5s

[codecov]

Codecov Report

Merging #14 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##             master   #14   +/-   ##
======================================
  Coverage        50%   50%           
  Complexity        2     2           
======================================
  Files             1     1           
  Lines             4     4           
======================================
  Hits              2     2           
  Misses            1     1           
  Partials          1     1

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[thomasrockhu]

Thanks @colddew!