Remove SonarCloud cache setup as it is now offered by default (Academ…

…ySoftwareFoundation#3792)

No need to configure the cache anymore,
SonarCloud now has automatic analysis caching. See:
https://docs.sonarcloud.io/advanced-setup/languages/c-c-objective-c/#analysis-cache.

Also, the filesystem cache was not persisted.

sonar-project.properties

@@ -19,7 +19,4 @@ sonar.cfamily.build-wrapper-output=build/bw_output
 sonar.cfamily.gcov.reportsPath=_coverage
 sonar.coverage.exclusions=src/iv/**,src/include/OpenImageIO/detail/pugixml/**,src/include/OpenImageIO/detail/fmt/**,src/libOpenImageIO/kissfft.hh
 
-sonar.cfamily.cache.enabled=true
-sonar.cfamily.cache.path=/tmp/sonarcache
-
 sonar.verbose=false