fix: Fatal error compiling: invalid flag: --release

[pinxiong]

Description

see issue #559

I referred to Maven: "Fatal error compiling: invalid flag: --release -> [Help 1]"

So, I think the simplest and best way to solve this issue is to update the Pre-Requisites in README.md

After I upgraded the JDK version, the project build successfully

[INFO] Attaching repackaged archive /***/java-sdk/examples/target/dapr-java-sdk-examples-exec.jar with classifier exec
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for dapr-sdk-parent 1.2.0-SNAPSHOT:
[INFO] 
[INFO] dapr-sdk-parent .................................... SUCCESS [  6.395 s]
[INFO] dapr-sdk-autogen ................................... SUCCESS [ 23.212 s]
[INFO] dapr-sdk ........................................... SUCCESS [ 28.708 s]
[INFO] dapr-sdk-actors .................................... SUCCESS [ 17.252 s]
[INFO] dapr-sdk-springboot ................................ SUCCESS [  4.066 s]
[INFO] dapr-sdk-examples .................................. SUCCESS [  6.887 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  01:28 min
[INFO] Finished at: 2021-06-03T11:19:20+08:00
[INFO] ------------------------------------------------------------------------
xxxx:java-sdk xxxx$ java -version
java version "11.0.9" 2020-10-20 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.9+7-LTS)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.9+7-LTS, mixed mode)
xxxx:java-sdk xxxx$ mvn -version
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /****/maven
Java version: 11.0.9, vendor: Oracle Corporation, runtime: /****/jdk-11.0.9.jdk/Contents/Home
Default locale: en_CN, platform encoding: UTF-8
OS name: "mac os x", version: "10.16", arch: "x86_64", family: "mac"

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #559

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[codecov]

Codecov Report

Merging #560 (4fba585) into master (b1e5438) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #560   +/-   ##
=========================================
  Coverage     80.52%   80.52%           
  Complexity      981      981           
=========================================
  Files            88       88           
  Lines          3024     3024           
  Branches        331      331           
=========================================
  Hits           2435     2435           
  Misses          423      423           
  Partials        166      166           

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