Fix cleanup script and update README

Fix cleanup script and update README

Update README.md about manually cleaning the work directory

Fix permissions of .scannerwork directory (SonarSource#57)

SC-9154 Update links in README

SC-9154 Update SonarCloud GitHub Action docs (SonarSource#54)

Update scanner cli version to 5.0 (SonarSource#51)

SC-6662 update README to use v3 of actions

SC-4361 Update sonar-scanner-cli to v4.8 (SonarSource#47)

update README to mention GH action for C and C++ (SonarSource#38)