Duplicate file in the shade jar #712

Bug Report

1. Describe the bug

There are duplicate files in the shade jar. If I unzip the tikv-client-java-3.3.0-SNAPSHOT.jar, there will be a promt:
replace META-INF/LICENSE? [y]es, [n]o, [A]ll, [N]one, [r]ename:.

I am tring to include tikv java client in my project's jar package, and in the gradle task, I cannot exclude the duplicated file, and after some debugging, I found out the duplicate file is in the jar itself. The Jar task of gradle will expand the jar archive before processing, and there is an error

2. Minimal reproduce step (Required)

1. Package the shade jar
2. Unzip it to some empty directory

3. What did you see instead (Required)

replace META-INF/LICENSE? [y]es, [n]o, [A]ll, [N]one, [r]ename:.

4. What did you expect to see? (Required)

Unzip success.

5. What are your Java Client and TiKV versions? (Required)

Latest master branch.
The version of TiKV is inrelevant because this is a bug of the packaging process.