Remove unnecessary jitpack preinstall

Since this uses the Maven Wrapper, this should no longer be necessary

Author: chadlwilson

jitpack.yml

@@ -1,10 +1,2 @@
 jdk:
   - openjdk21
-
-before_install:
-  - source "$HOME/.sdkman/bin/sdkman-init.sh"
-  - sdk update
-  - sdk install maven
-  - sdk install java 21.0.8.9-tem
-  - sdk use java 21.0.8.9-tem
-  - mvn -v