Source option 6 is no longer supported. Use 7 or later.

```
$ export JAVA_HOME=~/Library/Java/JavaVirtualMachines/adopt-openjdk-14.0.2/Contents/Home

$ mvn -version
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /Users/chenyisheng/softwares/apache-maven-3.6.3
Java version: 14.0.2, vendor: AdoptOpenJDK, runtime: /Users/chenyisheng/Library/Java/JavaVirtualMachines/adopt-openjdk-14.0.2/Contents/Home
Default locale: en_CN, platform encoding: UTF-8
OS name: "mac os x", version: "10.15.7", arch: "x86_64", family: "mac"

$ make build-ingestion-jar-no-tests REVISION=develop
...
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ feast-ingestion-spark ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 18 source files to /Users/chenyisheng/source/yiksanchan/feast-spark/spark/ingestion/target/test-classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] Source option 6 is no longer supported. Use 7 or later.
[ERROR] Target option 6 is no longer supported. Use 7 or later.
```