Fix deprecated uses of Redis#pipelined

Context: redis/redis-rb#1059

The following is deprecated
```ruby
redis.pipelined do
  redis.get(key)
end
```

And should be rewritten as:
```ruby
redis.pipelined do |pipeline|
  pipeline.get(key)
end
```

Functionally it makes no difference.

lib/mini_profiler/storage/redis_store.rb

@@ -189,9 +189,9 @@ def fetch_snapshots(batch_size: 200, &blk)
           iteration += 1
         end
         if corrupt_snapshots.size > 0
-          redis.pipelined do
-            redis.zrem(zset_key, corrupt_snapshots)
-            redis.hdel(hash_key, corrupt_snapshots)
+          redis.pipelined do |pipeline|
+            pipeline.zrem(zset_key, corrupt_snapshots)
+            pipeline.hdel(hash_key, corrupt_snapshots)
           end
         end
       end
@@ -202,9 +202,9 @@ def load_snapshot(id)
         begin
           Marshal.load(bytes)
         rescue
-          redis.pipelined do
-            redis.zrem(snapshot_zset_key(), id)
-            redis.hdel(hash_key, id)
+          redis.pipelined do |pipeline|
+            pipeline.zrem(snapshot_zset_key(), id)
+            pipeline.hdel(hash_key, id)
           end
           nil
         end
@@ -253,11 +253,11 @@ def cached_redis_eval(script, script_sha, reraise: true, argv: [], keys: [])
 
       # only used in tests
       def wipe_snapshots_data
-        redis.pipelined do
-          redis.del(snapshot_counter_key())
-          redis.del(snapshot_zset_key())
-          redis.del(snapshot_hash_key())
-        end
+        redis.del(
+          snapshot_counter_key(),
+          snapshot_zset_key(), 
+          snapshot_hash_key(),
+        )
       end
     end
   end