exercises(raindrops): sync metadata

Reflect the upstream changes [1][2].

[1] exercism/problem-specifications@b0e6f5feab4c
[2] exercism/problem-specifications@3826da50b109

exercises/practice/raindrops/.meta/config.json

@@ -13,7 +13,7 @@
       ".meta/example.zig"
     ]
   },
-  "blurb": "Convert a number to a string, the content of which depends on the number's factors.",
+  "blurb": "Convert a number into its corresponding raindrop sounds - Pling, Plang and Plong.",
   "source": "A variation on FizzBuzz, a famous technical interview question that is intended to weed out potential candidates. That question is itself derived from Fizz Buzz, a popular children's game for teaching division.",
   "source_url": "https://en.wikipedia.org/wiki/Fizz_buzz"
 }