crashreportclient: add build variant metadata

This will make it easier to reproduce the build that crashed.

Note: we should be able to use the build ID (build timestamp), but the
git tag is not the same as the build ID currently. This is a problem and
should be fixed in the future.

Gitlab: #1454
Change-Id: I8c6e25a685421398eef3052a9f48681ac369926c

src/app/crashreportclient.h

@@ -109,6 +109,9 @@ protected:
         {"client_sha", APP_VERSION_STRING},
         {"jamicore_sha", CORE_VERSION_STRING},
         {"build_id", QString(VERSION_STRING)},
+#if defined(Q_OS_WIN) && defined(BETA)
+        {"build_variant", "beta"},
+#endif
     };
 };