[KYUUBI #963] Bump up maven-download-plugin to 1.6.6

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### _Why are the changes needed?_
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Bump up maven-download-plugin to 1.6.6

### _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/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #965 from wangxuan0816/kyuubi-963.

Closes #963

291c367 [wangxuan0816] [KYUUBI #963] Bump up maven-download-plugin to 1.6.6

Authored-by: wangxuan0816 <1421615117@qq.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>
(cherry picked from commit 682ec1c)
Signed-off-by: Cheng Pan <chengpan@apache.org>

pom.xml

@@ -194,7 +194,7 @@
         <maven.plugin.compiler.version>3.8.1</maven.plugin.compiler.version>
         <maven.plugin.dependency.version>3.1.1</maven.plugin.dependency.version>
         <maven.plugin.deploy.version>3.0.0-M1</maven.plugin.deploy.version>
-        <maven.plugin.download.version>1.6.0</maven.plugin.download.version>
+        <maven.plugin.download.version>1.6.6</maven.plugin.download.version>
         <maven.plugin.gpg.version>3.0.1</maven.plugin.gpg.version>
         <maven.plugin.javadoc.version>3.3.0</maven.plugin.javadoc.version>
         <!-- DO NOT bump 4.4.0, see https://github.com/apache/incubator-kyuubi/pull/441 -->