[ci][docs] Mount the alma10 ccache volume for the doxygen job.

Author: hageboeck

.github/workflows/root-docs-ci.yml

@@ -46,6 +46,8 @@ jobs:
     container:
       image: registry.cern.ch/root-ci/alma10:buildready
       options: '--security-opt label=disable --rm'
+      volumes:
+        - alma10_ccache_volume:/github/home/.cache/ccache
       env:
         OS_APPLICATION_CREDENTIAL_ID: '7f5b64a265244623a3a933308569bdba'
         OS_APPLICATION_CREDENTIAL_SECRET: ${{ secrets.OS_APPLICATION_CREDENTIAL_SECRET }}