Updated cache action to v4 #93

Job	Run time
mvn (full-build-jdk11, 11, -Pfull-build apache-rat:check verify -DskipTests spotbugs:check checks...	3m 33s
mvn (full-build-jdk8, 8, -Pfull-build apache-rat:check verify -DskipTests spotbugs:check checksty...	3m 6s
mvn (full-build-cppunit-tests, 11, -Pfull-build verify -Dtest=_ -DfailIfNoTests=false)	2h 32m 9s
mvn (full-build-java-tests, 11, -Pfull-build verify -Dsurefire-forkcount=1 -DskipCppUnit -Dsurefi...	1h 5m 35s
mvn (full-build-cppunit-tests, 11, -Pfull-build verify -Dtest=_ -DfailIfNoTests=false)	4h 2m 49s
mvn (full-build-java-tests, 11, -Pfull-build verify -Dsurefire-forkcount=1 -DskipCppUnit -Dsurefi...	1h 5m 35s
mvn (full-build-jdk8, 8, -Pfull-build apache-rat:check verify -DskipTests spotbugs:check checksty...	3m 6s
mvn (full-build-jdk11, 11, -Pfull-build apache-rat:check verify -DskipTests spotbugs:check checks...	3m 33s
mvn (full-build-jdk8, 8, -Pfull-build apache-rat:check verify -DskipTests spotbugs:check checksty...	3m 3s
mvn (full-build-cppunit-tests, 11, -Pfull-build verify -Dtest=_ -DfailIfNoTests=false)	6h 0m 16s
mvn (full-build-java-tests, 11, -Pfull-build verify -Dsurefire-forkcount=1 -DskipCppUnit -Dsurefi...	1h 5m 52s
mvn (full-build-jdk11, 11, -Pfull-build apache-rat:check verify -DskipTests spotbugs:check checks...	3m 26s
	16h 12m 3s

Provide feedback