[azp] Enable pretty code coverage results xml (#946)

Author: kcudnik

.azure-pipelines/build-template.yml

@@ -129,7 +129,7 @@ jobs:
         make check
         gcovr --version
         find SAI/meta -name "*.gc*" | xargs rm -vf
-        gcovr -r ./ -e ".*/SAI/.*" -e ".+/json.hpp" -e "swss/.+" -e ".*/.libs/.*" -e ".*/debian/.*" --exclude-unreachable-branches --exclude-throw-branches -x -o coverage.xml
+        gcovr -r ./ -e ".*/SAI/.*" -e ".+/json.hpp" -e "swss/.+" -e ".*/.libs/.*" -e ".*/debian/.*" --exclude-unreachable-branches --exclude-throw-branches -x --xml-pretty -o coverage.xml
       displayName: "Run sonic sairedis unit tests"
   - publish: $(System.DefaultWorkingDirectory)/
     artifact: ${{ parameters.artifact_name }}