docs: mention breaking changes in next release note

docs/changelog/0.5.0.md

@@ -93,6 +93,75 @@ Javadoc and JVM output:
     throw new IllegalArgumentException("URI is not absolute")
   }
 ```
+
+### Replace time_t fields with timespec in POSIX sys/stat.scala
+
+In order to support nanosecond resolution for `java.nio.file.attribute.BasicFileAttributes`, we introduce breaking changes to sys/stat struct.
+
+Previously, `stat` struct was defined as following and you were able to access second resolution file stat fields `st_atime`, `st_mtime` and `st_ctime` by `_7`, `_8` and `_9`.
+
+```scala
+type stat = CStruct13[
+  dev_t, // st_dev
+  dev_t, // st_rdev
+  ino_t, // st_ino
+  uid_t, // st_uid
+  gid_t, // st_gid
+  off_t, // st_size
+  time_t, // st_atime
+  time_t, // st_mtime
+  time_t, // st_ctime
+  blkcnt_t, // st_blocks
+  blksize_t, // st_blksize
+  nlink_t, // st_nlink
+  mode_t // st_mode
+]
+```
+
+Since 0.5.0, `stat` struct uses `timespec` for file stat fields. Therefore, you need to replace `_7`, `_8` and `_9` with `_7._1`, `_8._1` and `_9._1` to access those fields.
+
+```scala
+  type stat = CStruct13[
+    dev_t, // st_dev
+    dev_t, // st_rdev
+    ino_t, // st_ino
+    uid_t, // st_uid
+    gid_t, // st_gid
+    off_t, // st_size
+    timespec, // st_atim or st_atimespec
+    timespec, // st_mtim or st_mtimespec
+    timespec, // st_ctim or st_ctimespec
+    blkcnt_t, // st_blocks
+    blksize_t, // st_blksize
+    nlink_t, // st_nlink
+    mode_t // st_mode
+  ]
+```
+
+There is a helper implicit class `statOps`, which provides human-friendly field accessors like `st_dev` or `st_rdev`. It is recommended to use these fields from `statOps` rather than accessing fields by `_N`.
+
+For example, import `scala.scalanative.posix.timeOps._` and `scala.scalanative.posix.sys.statOps.statOps`, then you can get the last access time of a file by `st_atime` or `st_atim` field.
+
+```scala
+import scala.scalanative.unsafe._
+import scala.scalanative.posix.sys.stat
+import scala.scalanative.posix.timeOps._
+import scala.scalanative.posix.sys.statOps.statOps
+
+Zone { implicit z =>
+  val filepath = c"/path/to/file"
+  val stat = alloc[stat.stat]()
+  stat.stat(filepath, stat)
+  // directly get the last access time in second resolution
+  val atime = stat.st_atime
+  // get the last access time in second resolution from timespec
+  val atimesec = stat.st_atim.tv_sec 
+  // get access time in nanosecond resolution from timespec
+  val atimensec = stat.st_atim.tv_nsec
+}
+
+```
+
 ## Deprecated definitions 
 
 ### Removed in this version