Fix template function (#105)

src/services/grafanaCharts.js

@@ -4,7 +4,7 @@ const template = (props, value) => {
   const keys = Object.keys(props);
 
   return keys.reduce(
-    (current, key) => current.replace(`\${${key}}`, props[key]),
+    (current, key) => current.replace(`{${key}}`, props[key]),
     value
   );
 };