Fix wrong format string in alarm_pool_dump_key (#437)

Fixes the following warning when building for host

```
[...]/pico-sdk/src/common/pico_time/time.c: In function 'alarm_pool_dump_key':
[...]/pico-sdk/src/common/pico_time/time.c:282:15: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'uint64_t' {aka 'long long unsigned int'} [-Wformat=]
     printf("%ld", to_us_since_boot(get_entry(pool, id)->target));
             ~~^   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             %I64d
```

Author: jonathangjertsen

src/common/pico_time/time.c

@@ -5,6 +5,7 @@
  */
 
 #include <limits.h>
+#include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include "pico.h"
@@ -278,7 +279,7 @@ static void alarm_pool_dump_key(pheap_node_id_t id, void *user_data) {
 #if PICO_ON_DEVICE
     printf("%lld (hi %02x)", to_us_since_boot(get_entry(pool, id)->target), *get_entry_id_high(pool, id));
 #else
-    printf("%ld", to_us_since_boot(get_entry(pool, id)->target));
+    printf(PRIu64, to_us_since_boot(get_entry(pool, id)->target));
 #endif
 }