[KYUUBI-SHADED #50] Bump Maven 3.8.8

### _Why are the changes needed?_

The existing Maven 3.8.7 is removed from https://dist.apache.org/repos/dist/release/maven/maven-3/ by Maven team, which usually indicates it's an outdated version.

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [x] [Run test](https://kyuubi.readthedocs.io/en/master/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #50 from pan3793/maven-3.8.8.

2b4cc77 [Cheng Pan] Bump Maven 3.8.8

Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>
(cherry picked from commit 5ba26fa)
Signed-off-by: Cheng Pan <chengpan@apache.org>

pom.xml

@@ -85,7 +85,7 @@
 
     <properties>
         <java.version>1.8</java.version>
-        <maven.version>3.8.7</maven.version>
+        <maven.version>3.8.8</maven.version>
         <maven.compiler.source>${java.version}</maven.compiler.source>
         <maven.compiler.target>${java.version}</maven.compiler.target>