Fix PwmHttpClientTest on RHEL8

[blissjoe]

This resolved my issue - #647

Update selfcert key from 1024 to 2048

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for PWM Password Self Service 2.1.0-SNAPSHOT:
[INFO]
[INFO] PWM Password Self Service .......................... SUCCESS [ 57.459 s]
[INFO] PWM Password Self Service: Library JAR - Data Objects SUCCESS [ 18.002 s]
[INFO] PWM Password Self Service: Library JAR - Utilities . SUCCESS [ 22.678 s]
[INFO] PWM Password Self Service: Server JAR .............. SUCCESS [03:20 min]
[INFO] PWM Password Self Service: Angular Client JAR ...... SUCCESS [ 43.278 s]
[INFO] PWM Password Self Service: Server WAR .............. SUCCESS [03:02 min]
[INFO] PWM Password Self Service: Executable Server JAR ... SUCCESS [01:01 min]
[INFO] PWM Password Self Service: Data Service WAR ........ SUCCESS [ 24.369 s]
[INFO] PWM Password Self Service: REST Test Server WAR .... SUCCESS [ 11.043 s]
[INFO] PWM Password Self Service: Docker Image ............ SUCCESS [ 49.640 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 11:10 min
[INFO] Finished at: 2022-03-23T09:41:46-04:00
[INFO] ------------------------------------------------------------------------