task: make count column bigint.

We now have customers that exceed INT capacity, so we need to change
this to BIGINT in client_metrics_env_variants_daily as well

src/migrations/20240919083625-client-metrics-env-variants-daily-to-bigint.js

@@ -0,0 +1,7 @@
+exports.up = function(db, cb) {
+    db.runSql(`ALTER TABLE client_metrics_env_variants_daily ALTER COLUMN count TYPE BIGINT`, cb);
+};
+
+exports.down = function(db, cb) {
+    db.runSql(`ALTER TABLE client_metrics_env_variants_daily ALTER COLUMN count TYPE INT`, cb);
+};