build(Gradle): Increase the memory for building

Upcoming restructurings for the Gradle project seem to require more memory
when building. Maybe this is because more things can be built in parallel,
but it could also be related to [1]. Simply double memory for Gradle to be
on the safe side.

[1]: gradle/gradle#23698

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>

gradle.properties

@@ -16,7 +16,7 @@
 # License-Filename: LICENSE
 
 org.gradle.caching = true
-org.gradle.jvmargs = -Xmx512m -XX:MaxMetaspaceSize=256m -Dfile.encoding=UTF-8
+org.gradle.jvmargs = -Xmx1024m -XX:MaxMetaspaceSize=512m -Dfile.encoding=UTF-8
 org.gradle.parallel = true
 
 buildCacheRetentionDays = 7