input: Fix an incompatible pointer

This incompatible pointer causes the following error in gcc15:

```log
~/GitHub/fluent-bit/src/flb_input.c: In function 'flb_input_instance_init':
~/GitHub/fluent-bit/src/flb_input.c:1247:22: error: passing argument 1 of 'cmt_gauge_set' from incompatible pointer type [-Wincompatible-pointer-types]
 1247 |     cmt_gauge_set(ins->cmt_ring_buffer_writes, ts, 0, 1, (char *[]) {name});
      |                   ~~~^~~~~~~~~~~~~~~~~~~~~~~~
      |                      |
      |                      struct cmt_counter *
In file included from ~/GitHub/fluent-bit/include/fluent-bit/flb_upstream.h:34,
                 from ~/GitHub/fluent-bit/include/fluent-bit/flb_input.h:29,
                 from ~/GitHub/fluent-bit/src/flb_input.c:29:
~/GitHub/fluent-bit/lib/cmetrics/include/cmetrics/cmt_gauge.h:38:37: note: expected 'struct cmt_gauge *' but argument is of type 'struct cmt_counter *'
   38 | int cmt_gauge_set(struct cmt_gauge *gauge, uint64_t timestamp, double val,
      |                   ~~~~~~~~~~~~~~~~~~^~~~~
~/GitHub/fluent-bit/src/flb_network.c: In function 'flb_net_dns_lookup_context_create':
~/GitHub/fluent-bit/src/flb_network.c:1123:5: warning: 'ares_set_socket_functions' is deprecated: Use ares_set_socket_functions_ex instead [-Wdeprecated-declarations]
 1123 |     ares_set_socket_functions(lookup_context->ares_channel,
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~
```

Signed-off-by: Hiroshi Hatake <[email protected]>

Author: cosmo0920

src/flb_input.c

@@ -1244,7 +1244,7 @@ int flb_input_instance_init(struct flb_input_instance *ins,
                             "ring_buffer_writes_total",
                             "Number of ring buffer writes.",
                             1, (char *[]) {"name"});
-    cmt_gauge_set(ins->cmt_ring_buffer_writes, ts, 0, 1, (char *[]) {name});
+    cmt_counter_set(ins->cmt_ring_buffer_writes, ts, 0, 1, (char *[]) {name});
 
     /* fluentbit_input_ring_buffer_retries_total */
     ins->cmt_ring_buffer_retries = \