Sonarcloud: Enable caching

Signed-off-by: Felix Weilbach <felix.weilbach@nextcloud.com>

.github/workflows/sonarcloud.yml

@@ -17,6 +17,13 @@ jobs:
       - uses: actions/checkout@v2
         with:
           fetch-depth: 0 # Shallow clones should be disabled for a better relevancy of analysis
+
+      - name: Restore cache
+        uses: actions/cache@v2
+        with:
+          path: /cache
+          key: ${{ runner.os }}
+
       - name: Run build-wrapper
         run: |
           mkdir build

sonar-project.properties

@@ -5,3 +5,5 @@ sonar.exclusions=3rdparty/**
 sonar.language=c++
 sonar.cfamily.cache.enabled=false
 sonar.cfamily.threads=2
+sonar.cfamily.cache.enabled=true,
+sonar.cfamily.cache.path=/cache/sonarcloud