problem: tests might fail and prevent deployment

Solution: don't run tests on tags

This doesn't break anything, as tags was not built until now. Anyway, when building tags we really care about the release of the packages and not tests

appveyor.yml

@@ -210,7 +210,7 @@ test_script:
             echo "Running tests in parallel" &&
             set TEST_OPTIONS=%TEST_OPTIONS% -j5
          )
-  - cmd: ctest -C "%Configuration%" -V %TEST_OPTIONS%
+  - cmd: if "%APPVEYOR_REPO_TAG%"=="false" (ctest -C "%Configuration%" -V %TEST_OPTIONS%)
 
 deploy:
   - provider: BinTray